Android_verify/third_party/curl/share/man/man1/curl.1

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.TH curl 1 "2025-01-17" "curl 8.9.1" "curl Manual"
.SH NAME
curl \- transfer a URL
.SH SYNOPSIS
\fBcurl [options / URLs]\fP
.SH DESCRIPTION
\fBcurl\fP is a tool for transferring data from or to a server using URLs. It
supports these protocols: DICT, FILE, FTP, FTPS, GOPHER, GOPHERS, HTTP, HTTPS,
IMAP, IMAPS, LDAP, LDAPS, MQTT, POP3, POP3S, RTMP, RTMPS, RTSP, SCP, SFTP,
SMB, SMBS, SMTP, SMTPS, TELNET, TFTP, WS and WSS.

curl is powered by libcurl for all transfer\-related features. See
\fIlibcurl(3)\fP for details.
.SH URL
The URL syntax is protocol\-dependent. You find a detailed description in
RFC 3986.

If you provide a URL without a leading \fBprotocol://\fP scheme, curl guesses
what protocol you want. It then defaults to HTTP but assumes others based on
often\-used hostname prefixes. For example, for hostnames starting with "ftp."
curl assumes you want FTP.

You can specify any amount of URLs on the command line. They are fetched in a
sequential manner in the specified order unless you use \fI\-Z, \-\-parallel\fP. You can
specify command line options and URLs mixed and in any order on the command
line.

curl attempts to reuse connections when doing multiple transfers, so that
getting many files from the same server do not use multiple connects and setup
handshakes. This improves speed. Connection reuse can only be done for URLs
specified for a single command line invocation and cannot be performed between
separate curl runs.

Provide an IPv6 zone id in the URL with an escaped percentage sign. Like in
.nf

\&"http://[fe80::3%25eth0]/"
.fi

Everything provided on the command line that is not a command line option or
its argument, curl assumes is a URL and treats it as such.
.SH GLOBBING
You can specify multiple URLs or parts of URLs by writing lists within braces
or ranges within brackets. We call this "globbing".

Provide a list with three different names like this:
.nf

\&"http://site.{one,two,three}.com"
.fi

Do sequences of alphanumeric series by using [] as in:
.nf

\&"ftp://ftp.example.com/file[1\-100].txt"
.fi

With leading zeroes:
.nf

\&"ftp://ftp.example.com/file[001\-100].txt"
.fi

With letters through the alphabet:
.nf

\&"ftp://ftp.example.com/file[a\-z].txt"
.fi

Nested sequences are not supported, but you can use several ones next to each
other:
.nf

\&"http://example.com/archive[1996\-1999]/vol[1\-4]/part{a,b,c}.html"
.fi

You can specify a step counter for the ranges to get every Nth number or
letter:
.nf

\&"http://example.com/file[1\-100:10].txt"

\&"http://example.com/file[a\-z:2].txt"
.fi

When using [] or {} sequences when invoked from a command line prompt, you
probably have to put the full URL within double quotes to avoid the shell from
interfering with it. This also goes for other characters treated special, like
for example \(aq&\(aq, \(aq?\(aq and \(aq*\(aq.

Switch off globbing with \fI\-g, \-\-globoff\fP.
.SH VARIABLES
curl supports command line variables (added in 8.3.0). Set variables with
\fI\-\-variable\fP name=content or \fI\-\-variable\fP name@file (where "file" can be stdin if
set to a single dash (\-)).

Variable contents can be expanded in option parameters using "{{name}}" if the
option name is prefixed with "\fI\-\-expand\-\fP". This gets the contents of the
variable "name" inserted, or a blank if the name does not exist as a
variable. Insert "{{" verbatim in the string by prefixing it with a backslash,
like "\\{{".

You an access and expand environment variables by first importing them. You
can select to either require the environment variable to be set or you can
provide a default value in case it is not already set. Plain \fI\-\-variable\fP %name
imports the variable called \(aqname\(aq but exits with an error if that environment
variable is not already set. To provide a default value if it is not set, use
\fI\-\-variable\fP %name=content or \fI\-\-variable\fP %name@content.

Example. Get the USER environment variable into the URL, fail if USER is not
set:
.nf

-\-variable \(aq%USER\(aq
-\-expand\-url = "https://example.com/api/{{USER}}/method"
.fi

When expanding variables, curl supports a set of functions that can make the
variable contents more convenient to use. It can trim leading and trailing
white space with "trim", it can output the contents as a JSON quoted string
with "json", URL encode the string with "url" or base64 encode it with "b64".
To apply functions to a variable expansion, add them colon separated to the
right side of the variable. Variable content holding null bytes that are not
encoded when expanded cause error.

Example: get the contents of a file called $HOME/.secret into a variable
called "fix". Make sure that the content is trimmed and percent\-encoded when
sent as POST data:
.nf

-\-variable %HOME
-\-expand\-variable fix@{{HOME}}/.secret
-\-expand\-data "{{fix:trim:url}}"
https://example.com/
.fi

Command line variables and expansions were added in 8.3.0.
.SH OUTPUT
If not told otherwise, curl writes the received data to stdout. It can be
instructed to instead save that data into a local file, using the \fI\-o, \-\-output\fP or
\fI\-O, \-\-remote\-name\fP options. If curl is given multiple URLs to transfer on the
command line, it similarly needs multiple options for where to save them.

curl does not parse or otherwise "understand" the content it gets or writes as
output. It does no encoding or decoding, unless explicitly asked to with
dedicated command line options.
.SH PROTOCOLS
curl supports numerous protocols, or put in URL terms: schemes. Your
particular build may not support them all.
.IP DICT
Lets you lookup words using online dictionaries.
.IP FILE
Read or write local files. curl does not support accessing file:// URL
remotely, but when running on Microsoft Windows using the native UNC approach
works.
.IP FTP(S)
curl supports the File Transfer Protocol with a lot of tweaks and levers. With
or without using TLS.
.IP GOPHER(S)
Retrieve files.
.IP HTTP(S)
curl supports HTTP with numerous options and variations. It can speak HTTP
version 0.9, 1.0, 1.1, 2 and 3 depending on build options and the correct
command line options.
.IP IMAP(S)
Using the mail reading protocol, curl can download emails for you. With or
without using TLS.
.IP LDAP(S)
curl can do directory lookups for you, with or without TLS.
.IP MQTT
curl supports MQTT version 3. Downloading over MQTT equals subscribe to a
topic while uploading/posting equals publish on a topic. MQTT over TLS is not
supported (yet).
.IP POP3(S)
Downloading from a pop3 server means getting a mail. With or without using
TLS.
.IP RTMP(S)
The \fBRealtime Messaging Protocol\fP is primarily used to serve streaming media
and curl can download it.
.IP RTSP
curl supports RTSP 1.0 downloads.
.IP SCP
curl supports SSH version 2 scp transfers.
.IP SFTP
curl supports SFTP (draft 5) done over SSH version 2.
.IP SMB(S)
curl supports SMB version 1 for upload and download.
.IP SMTP(S)
Uploading contents to an SMTP server means sending an email. With or without
TLS.
.IP TELNET
Fetching a telnet URL starts an interactive session where it sends what it
reads on stdin and outputs what the server sends it.
.IP TFTP
curl can do TFTP downloads and uploads.
.IP WS(S)
WebSocket done over HTTP/1. WSS implies that it works over HTTPS.
.SH PROGRESS METER
curl normally displays a progress meter during operations, indicating the
amount of transferred data, transfer speeds and estimated time left, etc. The
progress meter displays the transfer rate in bytes per second. The suffixes
(k, M, G, T, P) are 1024 based. For example 1k is 1024 bytes. 1M is 1048576
bytes.

curl displays this data to the terminal by default, so if you invoke curl to
do an operation and it is about to write data to the terminal, it \fIdisables\fP
the progress meter as otherwise it would mess up the output mixing progress
meter and response data.

If you want a progress meter for HTTP POST or PUT requests, you need to
redirect the response output to a file, using shell redirect (>), \fI\-o, \-\-output\fP
or similar.

This does not apply to FTP upload as that operation does not spit out any
response data to the terminal.

If you prefer a progress bar instead of the regular meter, \fI\-#, \-\-progress\-bar\fP is
your friend. You can also disable the progress meter completely with the
\fI\-s, \-\-silent\fP option.
.SH VERSION
This man page describes curl 8.9.1. If you use a later version, chances
are this man page does not fully document it. If you use an earlier version,
this document tries to include version information about which specific
version that introduced changes.

You can always learn which the latest curl version is by running
.nf

curl https://curl.se/info
.fi

The online version of this man page is always showing the latest incarnation:
https://curl.se/docs/manpage.html
.SH OPTIONS
Options start with one or two dashes. Many of the options require an
additional value next to them. If provided text does not start with a dash, it
is presumed to be and treated as a URL.

The short "single\-dash" form of the options, \-d for example, may be used with
or without a space between it and its value, although a space is a recommended
separator. The long double\-dash form, \fI\-d, \-\-data\fP for example, requires a space
between it and its value.

Short version options that do not need any additional values can be used
immediately next to each other, like for example you can specify all the
options \fI\-O\fP, \fI\-L\fP and \fI\-v\fP at once as \fI\-OLv\fP.

In general, all boolean options are enabled with \--\fBoption\fP and yet again
disabled with \--\fBno\-\fPoption. That is, you use the same option name but
prefix it with "no\-". However, in this list we mostly only list and show the
-\-\fBoption\fP version of them.

When \fI\-:, \-\-next\fP is used, it resets the parser state and you start again with a
clean option state, except for the options that are global. Global options
retain their values and meaning even after \fI\-:, \-\-next\fP.

The following options are global: \fI\-\-fail\-early\fP, \fI\-\-libcurl\fP, \fI\-\-parallel\-immediate\fP, \fI\-\-parallel\-max\fP, \fI\-Z, \-\-parallel\fP, \fI\-#, \-\-progress\-bar\fP, \fI\-\-rate\fP, \fI\-S, \-\-show\-error\fP, \fI\-\-stderr\fP, \fI\-\-styled\-output\fP, \fI\-\-trace\-ascii\fP, \fI\-\-trace\-config\fP, \fI\-\-trace\-ids\fP, \fI\-\-trace\-time\fP, \fI\-\-trace\fP and \fI\-v, \-\-verbose\fP.
.IP "\-\-abstract\-unix\-socket <path>"
(HTTP) Connect through an abstract Unix domain socket, instead of using the network.
Note: netstat shows the path of an abstract socket prefixed with "@", however
the <path> argument should not have this leading character.

If --abstract-unix-socket is provided several times, the last set value is used.

Example:
.nf
 curl --abstract-unix-socket socketpath https://example.com
.fi

See also \fI\-\-unix\-socket\fP.
.IP "\-\-alt\-svc <filename>"
(HTTPS) Enable the alt\-svc parser. If the filename points to an existing alt\-svc cache
file, that gets used. After a completed transfer, the cache is saved to the
filename again if it has been modified.

Specify a "" filename (zero length) to avoid loading/saving and make curl just
handle the cache in memory.

If this option is used several times, curl loads contents from all the
files but the last one is used for saving.

--alt-svc can be used several times in a command line

Example:
.nf
 curl --alt-svc svc.txt https://example.com
.fi

Added in 7.64.1. See also \fI\-\-resolve\fP and \fI\-\-connect\-to\fP.
.IP "\-\-anyauth"
(HTTP) Figure out authentication method automatically, and use the most secure one
the remote site claims to support. This is done by first doing a request and
checking the response\-headers, thus possibly inducing an extra network
round\-trip. This option is used instead of setting a specific authentication
method, which you can do with \fI\-\-basic\fP, \fI\-\-digest\fP, \fI\-\-ntlm\fP, and \fI\-\-negotiate\fP.

Using \fI\-\-anyauth\fP is not recommended if you do uploads from stdin, since it may
require data to be sent twice and then the client must be able to rewind. If
the need should arise when uploading from stdin, the upload operation fails.

Used together with \fI\-u, \-\-user\fP.

Providing --anyauth multiple times has no extra effect.

Example:
.nf
 curl --anyauth --user me:pwd https://example.com
.fi

See also \fI\-\-proxy\-anyauth\fP, \fI\-\-basic\fP and \fI\-\-digest\fP.
.IP "\-a, \-\-append"
(FTP SFTP) When used in an upload, this option makes curl append to the target file
instead of overwriting it. If the remote file does not exist, it is
created. Note that this flag is ignored by some SFTP servers (including
OpenSSH).

Providing --append multiple times has no extra effect.
Disable it again with \-\-no-append.

Example:
.nf
 curl --upload-file local --append ftp://example.com/
.fi

See also \fI-r, \-\-range\fP and \fI-C, \-\-continue\-at\fP.
.IP "\-\-aws\-sigv4 <provider1[:prvdr2[:reg[:srv]]]>"
(HTTP) Use AWS V4 signature authentication in the transfer.

The provider argument is a string that is used by the algorithm when creating
outgoing authentication headers.

The region argument is a string that points to a geographic area of
a resources collection (region\-code) when the region name is omitted from
the endpoint.

The service argument is a string that points to a function provided by a cloud
(service\-code) when the service name is omitted from the endpoint.

If --aws-sigv4 is provided several times, the last set value is used.

Example:
.nf
 curl --aws-sigv4 "aws:amz:us-east-2:es" --user "key:secret" https://example.com
.fi

Added in 7.75.0. See also \fI\-\-basic\fP and \fI-u, \-\-user\fP.
.IP "\-\-basic"
(HTTP) Use HTTP Basic authentication with the remote host. This method is the default
and this option is usually pointless, unless you use it to override a
previously set option that sets a different authentication method (such as
\fI\-\-ntlm\fP, \fI\-\-digest\fP, or \fI\-\-negotiate\fP).

Used together with \fI\-u, \-\-user\fP.

Providing --basic multiple times has no extra effect.

Example:
.nf
 curl -u name:password --basic https://example.com
.fi

See also \fI\-\-proxy\-basic\fP.
.IP "\-\-ca\-native"
(TLS) Use the CA store from the native operating system to verify the peer. By
default, curl otherwise uses a CA store provided in a single file or
directory, but when using this option it interfaces the operating system\(aqs own
vault.

This option works for curl on Windows when built to use OpenSSL, wolfSSL
(added in 8.3.0) or GnuTLS (added in 8.5.0). When curl on Windows is built to
use Schannel, this feature is implied and curl then only uses the native CA
store.

Providing --ca-native multiple times has no extra effect.
Disable it again with \-\-no-ca-native.

Example:
.nf
 curl --ca-native https://example.com
.fi

Added in 8.2.0. See also \fI\-\-cacert\fP, \fI\-\-capath\fP and \fI-k, \-\-insecure\fP.
.IP "\-\-cacert <file>"
(TLS) Use the specified certificate file to verify the peer. The file may contain
multiple CA certificates. The certificate(s) must be in PEM format. Normally
curl is built to use a default file for this, so this option is typically used
to alter that default file.

curl recognizes the environment variable named \(aqCURL_CA_BUNDLE\(aq if it is set
and the TLS backend is not Schannel, and uses the given path as a path to a CA
cert bundle. This option overrides that variable.

The windows version of curl automatically looks for a CA certs file named
\(aqcurl\-ca\-bundle.crt\(aq, either in the same directory as curl.exe, or in the
Current Working Directory, or in any folder along your PATH.

(iOS and macOS only) If curl is built against Secure Transport, then this
option is supported for backward compatibility with other SSL engines, but it
should not be set. If the option is not set, then curl uses the certificates
in the system and user Keychain to verify the peer, which is the preferred
method of verifying the peer\(aqs certificate chain.

(Schannel only) This option is supported for Schannel in Windows 7 or later
(added in 7.60.0). This option is supported for backward compatibility with
other SSL engines; instead it is recommended to use Windows\(aq store of root
certificates (the default for Schannel).

If --cacert is provided several times, the last set value is used.

Example:
.nf
 curl --cacert CA-file.txt https://example.com
.fi

See also \fI\-\-capath\fP and \fI-k, \-\-insecure\fP.
.IP "\-\-capath <dir>"
(TLS) Use the specified certificate directory to verify the peer. Multiple paths can
be provided by separated with colon (":") (e.g. "path1:path2:path3"). The
certificates must be in PEM format, and if curl is built against OpenSSL, the
directory must have been processed using the c_rehash utility supplied with
OpenSSL. Using \fI\-\-capath\fP can allow OpenSSL\-powered curl to make SSL\-connections
much more efficiently than using \fI\-\-cacert\fP if the \fI\-\-cacert\fP file contains many
CA certificates.

If this option is set, the default capath value is ignored.

If --capath is provided several times, the last set value is used.

Example:
.nf
 curl --capath /local/directory https://example.com
.fi

See also \fI\-\-cacert\fP and \fI-k, \-\-insecure\fP.
.IP "\-E, \-\-cert <certificate[:password]>"
(TLS) Use the specified client certificate file when getting a file with HTTPS, FTPS
or another SSL\-based protocol. The certificate must be in PKCS#12 format if
using Secure Transport, or PEM format if using any other engine. If the
optional password is not specified, it is queried for on the terminal. Note
that this option assumes a certificate file that is the private key and the
client certificate concatenated. See \fI\-E, \-\-cert\fP and \fI\-\-key\fP to specify them
independently.

In the <certificate> portion of the argument, you must escape the character
\&":" as "\\:" so that it is not recognized as the password delimiter. Similarly,
you must escape the double quote character as \\" so that it is not recognized
as an escape character.

If curl is built against OpenSSL library, and the engine pkcs11 is available,
then a PKCS#11 URI (RFC 7512) can be used to specify a certificate located in
a PKCS#11 device. A string beginning with "pkcs11:" is interpreted as a
PKCS#11 URI. If a PKCS#11 URI is provided, then the \fI\-\-engine\fP option is set as
\&"pkcs11" if none was provided and the \fI\-\-cert\-type\fP option is set as "ENG" if
none was provided.

(iOS and macOS only) If curl is built against Secure Transport, then the
certificate string can either be the name of a certificate/private key in the
system or user keychain, or the path to a PKCS#12\-encoded certificate and
private key. If you want to use a file from the current directory, please
precede it with "./" prefix, in order to avoid confusion with a nickname.

(Schannel only) Client certificates must be specified by a path expression to
a certificate store. (Loading \fIPFX\fP is not supported; you can import it to a
store first). You can use "<store location>\\<store name>\\<thumbprint>"
to refer to a certificate in the system certificates store, for example,
\fI"CurrentUser\\MY\\934a7ac6f8a5d579285a74fa61e19f23ddfe8d7a"\fP. Thumbprint is
usually a SHA\-1 hex string which you can see in certificate details. Following
store locations are supported: \fICurrentUser\fP, \fILocalMachine\fP,
\fICurrentService\fP, \fIServices\fP, \fICurrentUserGroupPolicy\fP,
\fILocalMachineGroupPolicy\fP and \fILocalMachineEnterprise\fP.

If --cert is provided several times, the last set value is used.

Example:
.nf
 curl --cert certfile --key keyfile https://example.com
.fi

See also \fI\-\-cert\-type\fP, \fI\-\-key\fP and \fI\-\-key\-type\fP.
.IP "\-\-cert\-status"
(TLS) Verify the status of the server certificate by using the Certificate Status
Request (aka. OCSP stapling) TLS extension.

If this option is enabled and the server sends an invalid (e.g. expired)
response, if the response suggests that the server certificate has been
revoked, or no response at all is received, the verification fails.

This support is currently only implemented in the OpenSSL and GnuTLS backends.

Providing --cert-status multiple times has no extra effect.
Disable it again with \-\-no-cert-status.

Example:
.nf
 curl --cert-status https://example.com
.fi

See also \fI\-\-pinnedpubkey\fP.
.IP "\-\-cert\-type <type>"
(TLS) Set type of the provided client certificate. PEM, DER, ENG and P12 are
recognized types.

The default type depends on the TLS backend and is usually PEM, however for
Secure Transport and Schannel it is P12. If \fI\-E, \-\-cert\fP is a pkcs11: URI then ENG is
the default type.

If --cert-type is provided several times, the last set value is used.

Example:
.nf
 curl --cert-type PEM --cert file https://example.com
.fi

See also \fI-E, \-\-cert\fP, \fI\-\-key\fP and \fI\-\-key\-type\fP.
.IP "\-\-ciphers <list of ciphers>"
(TLS) Specifies which ciphers to use in the connection. The list of ciphers must
specify valid ciphers. Read up on SSL cipher list details on this URL:

https://curl.se/docs/ssl\-ciphers.html

If --ciphers is provided several times, the last set value is used.

Example:
.nf
 curl --ciphers ECDHE-ECDSA-AES256-CCM8 https://example.com
.fi

See also \fI\-\-tlsv1.3\fP, \fI\-\-tls13\-ciphers\fP and \fI\-\-proxy\-ciphers\fP.
.IP "\-\-compressed"
(HTTP) Request a compressed response using one of the algorithms curl supports, and
automatically decompress the content.

Response headers are not modified when saved, so if they are "interpreted"
separately again at a later point they might appear to be saying that the
content is (still) compressed; while in fact it has already been decompressed.

If this option is used and the server sends an unsupported encoding, curl
reports an error. This is a request, not an order; the server may or may not
deliver data compressed.

Providing --compressed multiple times has no extra effect.
Disable it again with \-\-no-compressed.

Example:
.nf
 curl --compressed https://example.com
.fi

See also \fI\-\-compressed\-ssh\fP.
.IP "\-\-compressed\-ssh"
(SCP SFTP) Enables built\-in SSH compression. This is a request, not an order; the server
may or may not do it.

Providing --compressed-ssh multiple times has no extra effect.
Disable it again with \-\-no-compressed-ssh.

Example:
.nf
 curl --compressed-ssh sftp://example.com/
.fi

See also \fI\-\-compressed\fP.
.IP "\-K, \-\-config <file>"
Specify a text file to read curl arguments from. The command line arguments
found in the text file are used as if they were provided on the command
line.

Options and their parameters must be specified on the same line in the file,
separated by whitespace, colon, or the equals sign. Long option names can
optionally be given in the config file without the initial double dashes and
if so, the colon or equals characters can be used as separators. If the option
is specified with one or two dashes, there can be no colon or equals character
between the option and its parameter.

If the parameter contains whitespace or starts with a colon (:) or equals sign
(=), it must be specified enclosed within double quotes ("like this"). Within
double quotes the following escape sequences are available: \\\\, \\", \\t, \\n, \\r
and \\v. A backslash preceding any other letter is ignored.

If the first non\-blank column of a config line is a \(aq#\(aq character, that line
is treated as a comment.

Only write one option per physical line in the config file. A single line is
required to be no more than 10 megabytes (since 8.2.0).

Specify the filename to \fI\-K, \-\-config\fP as minus "\-" to make curl read the file from
stdin.

Note that to be able to specify a URL in the config file, you need to specify
it using the \fI\-\-url\fP option, and not by simply writing the URL on its own
line. So, it could look similar to this:
.nf

url = "https://curl.se/docs/"

# \--\- Example file \--\-
# this is a comment
url = "example.com"
output = "curlhere.html"
user\-agent = "superagent/1.0"

# and fetch another URL too
url = "example.com/docs/manpage.html"
-O
referer = "http://nowhereatall.example.com/"
# \--\- End of example file \--\-
.fi

When curl is invoked, it (unless \fI\-q, \-\-disable\fP is used) checks for a default
config file and uses it if found, even when \fI\-K, \-\-config\fP is used. The default
config file is checked for in the following places in this order:

1) \fB"$CURL_HOME/.curlrc"\fP

2) \fB"$XDG_CONFIG_HOME/curlrc"\fP (Added in 7.73.0)

3) \fB"$HOME/.curlrc"\fP

4) Windows: \fB"%USERPROFILE%\\.curlrc"\fP

5) Windows: \fB"%APPDATA%\\.curlrc"\fP

6) Windows: \fB"%USERPROFILE%\\Application Data\\.curlrc"\fP

7) Non\-Windows: use getpwuid to find the home directory

8) On Windows, if it finds no \fI.curlrc\fP file in the sequence described above, it
checks for one in the same directory the curl executable is placed.

On Windows two filenames are checked per location: \fI.curlrc\fP and \fI_curlrc\fP,
preferring the former. Older versions on Windows checked for \fI_curlrc\fP only.

--config can be used several times in a command line

Example:
.nf
 curl --config file.txt https://example.com
.fi

See also \fI-q, \-\-disable\fP.
.IP "\-\-connect\-timeout <seconds>"
Maximum time in seconds that you allow curl\(aqs connection to take. This only
limits the connection phase, so if curl connects within the given period it
continues \- if not it exits.

This option accepts decimal values. The decimal value needs
to be provided using a dot (.) as decimal separator \- not the local version
even if it might be using another separator.

The connection phase is considered complete when the DNS lookup and requested
TCP, TLS or QUIC handshakes are done.

If --connect-timeout is provided several times, the last set value is used.

Examples:
.nf
 curl --connect-timeout 20 https://example.com
 curl --connect-timeout 3.14 https://example.com
.fi

See also \fI-m, \-\-max\-time\fP.
.IP "\-\-connect\-to <HOST1:PORT1:HOST2:PORT2>"
For a request intended for the "HOST1:PORT1" pair, connect to "HOST2:PORT2"
instead. This option is only used to establish the network connection. It does
NOT affect the hostname/port number that is used for TLS/SSL (e.g. SNI,
certificate verification) or for the application protocols.

\&"HOST1" and "PORT1" may be empty strings, meaning any host or any port number.
\&"HOST2" and "PORT2" may also be empty strings, meaning use the request\(aqs
original hostname and port number.

A hostname specified to this option is compared as a string, so it needs to
match the name used in request URL. It can be either numerical such as
\&"127.0.0.1" or the full host name such as "example.org".

Example: redirect connects from the example.com hostname to 127.0.0.1
independently of port number:
.nf

curl \--connect\-to example.com::127.0.0.1: https://example.com/
.fi

Example: redirect connects from all hostnames to 127.0.0.1 independently of
port number:
.nf

curl \--connect\-to ::127.0.0.1: http://example.com/
.fi

--connect-to can be used several times in a command line

Example:
.nf
 curl --connect-to example.com:443:example.net:8443 https://example.com
.fi

See also \fI\-\-resolve\fP and \fI-H, \-\-header\fP.
.IP "\-C, \-\-continue\-at <offset>"
Resume a previous transfer from the given byte offset. The given offset is the
exact number of bytes that are skipped, counting from the beginning of the
source file before it is transferred to the destination. If used with uploads,
the FTP server command SIZE is not used by curl.

Use "\-C \-" to instruct curl to automatically find out where/how to resume the
transfer. It then uses the given output/input files to figure that out.

If --continue-at is provided several times, the last set value is used.

Examples:
.nf
 curl -C - https://example.com
 curl -C 400 https://example.com
.fi

See also \fI-r, \-\-range\fP.
.IP "\-b, \-\-cookie <data|filename>"
(HTTP) Pass the data to the HTTP server in the Cookie header. It is supposedly the
data previously received from the server in a "Set\-Cookie:" line. The data
should be in the format "NAME1=VALUE1; NAME2=VALUE2" or as a single filename.

When given a set of specific cookies and not a filename, it makes curl use the
cookie header with this content explicitly in all outgoing request(s). If
multiple requests are done due to authentication, followed redirects or
similar, they all get this cookie header passed on.

If no "=" symbol is used in the argument, it is instead treated as a filename
to read previously stored cookie from. This option also activates the cookie
engine which makes curl record incoming cookies, which may be handy if you are
using this in combination with the \fI\-L, \-\-location\fP option or do multiple URL
transfers on the same invoke.

If the filename is a single minus ("\-"), curl reads the contents from stdin.
If the filename is an empty string ("") and is the only cookie input, curl
activates the cookie engine without any cookies.

The file format of the file to read cookies from should be plain HTTP headers
(Set\-Cookie style) or the Netscape/Mozilla cookie file format.

The file specified with \fI\-b, \-\-cookie\fP is only used as input. No cookies are written
to that file. To store cookies, use the \fI\-c, \-\-cookie\-jar\fP option.

If you use the Set\-Cookie file format and do not specify a domain then the
cookie is not sent since the domain never matches. To address this, set a
domain in Set\-Cookie line (doing that includes subdomains) or preferably: use
the Netscape format.

Users often want to both read cookies from a file and write updated cookies
back to a file, so using both \fI\-b, \-\-cookie\fP and \fI\-c, \-\-cookie\-jar\fP in the same command
line is common.

If curl is built with PSL (\fBPublic Suffix List\fP) support, it detects and
discards cookies that are specified for such suffix domains that should not be
allowed to have cookies. If curl is \fInot\fP built with PSL support, it has no
ability to stop super cookies.

--cookie can be used several times in a command line

Examples:
.nf
 curl -b "" https://example.com
 curl -b cookiefile https://example.com
 curl -b cookiefile -c cookiefile https://example.com
 curl -b name=Jane https://example.com
.fi

See also \fI-c, \-\-cookie\-jar\fP and \fI-j, \-\-junk\-session\-cookies\fP.
.IP "\-c, \-\-cookie\-jar <filename>"
(HTTP) Specify to which file you want curl to write all cookies after a completed
operation. Curl writes all cookies from its in\-memory cookie storage to the
given file at the end of operations. Even if no cookies are known, a file is
created so that it removes any formerly existing cookies from the file. The
file uses the Netscape cookie file format. If you set the filename to a single
minus, "\-", the cookies are written to stdout.

The file specified with \fI\-c, \-\-cookie\-jar\fP is only used for output. No cookies are
read from the file. To read cookies, use the \fI\-b, \-\-cookie\fP option. Both options
can specify the same file.

This command line option activates the cookie engine that makes curl record
and use cookies. The \fI\-b, \-\-cookie\fP option also activates it.

If the cookie jar cannot be created or written to, the whole curl operation
does not fail or even report an error clearly. Using \fI\-v, \-\-verbose\fP gets a warning
displayed, but that is the only visible feedback you get about this possibly
lethal situation.

If --cookie-jar is provided several times, the last set value is used.

Examples:
.nf
 curl -c store-here.txt https://example.com
 curl -c store-here.txt -b read-these https://example.com
.fi

See also \fI-b, \-\-cookie\fP and \fI-j, \-\-junk\-session\-cookies\fP.
.IP "\-\-create\-dirs"
When used in conjunction with the \fI\-o, \-\-output\fP option, curl creates the necessary
local directory hierarchy as needed. This option creates the directories
mentioned with the \fI\-o, \-\-output\fP option combined with the path possibly set with
\fI\-\-output\-dir\fP. If the combined output filename uses no directory, or if the
directories it mentions already exist, no directories are created.

Created directories are made with mode 0750 on unix style file systems.

To create remote directories when using FTP or SFTP, try \fI\-\-ftp\-create\-dirs\fP.

Providing --create-dirs multiple times has no extra effect.
Disable it again with \-\-no-create-dirs.

Example:
.nf
 curl --create-dirs --output local/dir/file https://example.com
.fi

See also \fI\-\-ftp\-create\-dirs\fP and \fI\-\-output\-dir\fP.
.IP "\-\-create\-file\-mode <mode>"
(SFTP SCP FILE) When curl is used to create files remotely using one of the supported
protocols, this option allows the user to set which \(aqmode\(aq to set on the file
at creation time, instead of the default 0644.

This option takes an octal number as argument.

If --create-file-mode is provided several times, the last set value is used.

Example:
.nf
 curl --create-file-mode 0777 -T localfile sftp://example.com/new
.fi

Added in 7.75.0. See also \fI\-\-ftp\-create\-dirs\fP.
.IP "\-\-crlf"
(FTP SMTP) Convert line feeds to carriage return plus line feeds in upload. Useful for
\fBMVS (OS/390)\fP.

Providing --crlf multiple times has no extra effect.
Disable it again with \-\-no-crlf.

Example:
.nf
 curl --crlf -T file ftp://example.com/
.fi

See also \fI-B, \-\-use\-ascii\fP.
.IP "\-\-crlfile <file>"
(TLS) Provide a file using PEM format with a Certificate Revocation List that may
specify peer certificates that are to be considered revoked.

If --crlfile is provided several times, the last set value is used.

Example:
.nf
 curl --crlfile rejects.txt https://example.com
.fi

See also \fI\-\-cacert\fP and \fI\-\-capath\fP.
.IP "\-\-curves <list>"
(TLS) Set specific curves to use during SSL session establishment according to RFC
8422, 5.1. Multiple algorithms can be provided by separating them with ":"
(e.g. "X25519:P\-521"). The parameter is available identically in the OpenSSL
\&"s_client" and "s_server" utilities.

\fI\-\-curves\fP allows a OpenSSL powered curl to make SSL\-connections with exactly
the (EC) curve requested by the client, avoiding nontransparent client/server
negotiations.

If this option is set, the default curves list built into OpenSSL are ignored.

If --curves is provided several times, the last set value is used.

Example:
.nf
 curl --curves X25519 https://example.com
.fi

Added in 7.73.0. See also \fI\-\-ciphers\fP.
.IP "\-d, \-\-data <data>"
(HTTP MQTT) Sends the specified data in a POST request to the HTTP server, in the same way
that a browser does when a user has filled in an HTML form and presses the
submit button. This option makes curl pass the data to the server using the
content\-type application/x\-www\-form\-urlencoded. Compare to \fI\-F, \-\-form\fP.

\fI\-\-data\-raw\fP is almost the same but does not have a special interpretation of
the @ character. To post data purely binary, you should instead use the
\fI\-\-data\-binary\fP option. To URL\-encode the value of a form field you may use
\fI\-\-data\-urlencode\fP.

If any of these options is used more than once on the same command line, the
data pieces specified are merged with a separating &\-symbol. Thus, using
\(aq\-d name=daniel \-d skill=lousy\(aq would generate a post chunk that looks like
\(aqname=daniel&skill=lousy\(aq.

If you start the data with the letter @, the rest should be a filename to read
the data from, or \- if you want curl to read the data from stdin. Posting data
from a file named \(aqfoobar\(aq would thus be done with \fI\-d, \-\-data\fP @foobar. When \fI\-d, \-\-data\fP
is told to read from a file like that, carriage returns, newlines and null
bytes are stripped out. If you do not want the @ character to have a special
interpretation use \fI\-\-data\-raw\fP instead.

The data for this option is passed on to the server exactly as provided on the
command line. curl does not convert, change or improve it. It is up to the
user to provide the data in the correct form.

--data can be used several times in a command line

Examples:
.nf
 curl -d "name=curl" https://example.com
 curl -d "name=curl" -d "tool=cmdline" https://example.com
 curl -d @filename https://example.com
.fi

This option is mutually exclusive with \fI-F, \-\-form\fP, \fI-I, \-\-head\fP and \fI-T, \-\-upload\-file\fP.
See also \fI\-\-data\-binary\fP, \fI\-\-data\-urlencode\fP and \fI\-\-data\-raw\fP.
.IP "\-\-data\-ascii <data>"
(HTTP) This option is just an alias for \fI\-d, \-\-data\fP.

--data-ascii can be used several times in a command line

Example:
.nf
 curl --data-ascii @file https://example.com
.fi

See also \fI\-\-data\-binary\fP, \fI\-\-data\-raw\fP and \fI\-\-data\-urlencode\fP.
.IP "\-\-data\-binary <data>"
(HTTP) Post data exactly as specified with no extra processing whatsoever.

If you start the data with the letter @, the rest should be a filename. Data
is posted in a similar manner as \fI\-d, \-\-data\fP does, except that newlines and
carriage returns are preserved and conversions are never done.

Like \fI\-d, \-\-data\fP the default content\-type sent to the server is
application/x\-www\-form\-urlencoded. If you want the data to be treated as
arbitrary binary data by the server then set the content\-type to octet\-stream:
-H "Content\-Type: application/octet\-stream".

If this option is used several times, the ones following the first append
data as described in \fI\-d, \-\-data\fP.

--data-binary can be used several times in a command line

Example:
.nf
 curl --data-binary @filename https://example.com
.fi

See also \fI\-\-data\-ascii\fP.
.IP "\-\-data\-raw <data>"
(HTTP) Post data similarly to \fI\-d, \-\-data\fP but without the special interpretation of the @
character.

--data-raw can be used several times in a command line

Examples:
.nf
 curl --data-raw "hello" https://example.com
 curl --data-raw "@at@at@" https://example.com
.fi

See also \fI-d, \-\-data\fP.
.IP "\-\-data\-urlencode <data>"
(HTTP) Post data, similar to the other \fI\-d, \-\-data\fP options with the exception that this
performs URL\-encoding.

To be CGI\-compliant, the <data> part should begin with a \fIname\fP followed by
a separator and a content specification. The <data> part can be passed to
curl using one of the following syntaxes:
.RS
.IP content
URL\-encode the content and pass that on. Just be careful so that the content
does not contain any "=" or "@" symbols, as that makes the syntax match one of
the other cases below!
.IP =content
URL\-encode the content and pass that on. The preceding "=" symbol is not
included in the data.
.IP name=content
URL\-encode the content part and pass that on. Note that the name part is
expected to be URL\-encoded already.
.IP @filename
load data from the given file (including any newlines), URL\-encode that data
and pass it on in the POST.
.IP name@filename
load data from the given file (including any newlines), URL\-encode that data
and pass it on in the POST. The name part gets an equal sign appended,
resulting in \fIname=urlencoded\-file\-content\fP. Note that the name is expected to
be URL\-encoded already.
.RE
.IP

--data-urlencode can be used several times in a command line

Examples:
.nf
 curl --data-urlencode name=val https://example.com
 curl --data-urlencode =encodethis https://example.com
 curl --data-urlencode name@file https://example.com
 curl --data-urlencode @fileonly https://example.com
.fi

See also \fI-d, \-\-data\fP and \fI\-\-data\-raw\fP.
.IP "\-\-delegation <LEVEL>"
(GSS/kerberos) Set LEVEL what curl is allowed to delegate when it comes to user credentials.
.RS
.IP none
Do not allow any delegation.
.IP policy
Delegates if and only if the OK\-AS\-DELEGATE flag is set in the Kerberos
service ticket, which is a matter of realm policy.
.IP always
Unconditionally allow the server to delegate.
.RE
.IP

If --delegation is provided several times, the last set value is used.

Example:
.nf
 curl --delegation "none" https://example.com
.fi

See also \fI-k, \-\-insecure\fP and \fI\-\-ssl\fP.
.IP "\-\-digest"
(HTTP) Enables HTTP Digest authentication. This authentication scheme avoids sending
the password over the wire in clear text. Use this in combination with the
normal \fI\-u, \-\-user\fP option to set username and password.

Providing --digest multiple times has no extra effect.
Disable it again with \-\-no-digest.

Example:
.nf
 curl -u name:password --digest https://example.com
.fi

This option is mutually exclusive with \fI\-\-basic\fP, \fI\-\-ntlm\fP and \fI\-\-negotiate\fP.
See also \fI-u, \-\-user\fP, \fI\-\-proxy\-digest\fP and \fI\-\-anyauth\fP.
.IP "\-q, \-\-disable"
If used as the \fBfirst\fP parameter on the command line, the \fIcurlrc\fP config
file is not read or used. See the \fI\-K, \-\-config\fP for details on the default config
file search path.

Providing --disable multiple times has no extra effect.
Disable it again with \-\-no-disable.

Example:
.nf
 curl -q https://example.com
.fi

See also \fI-K, \-\-config\fP.
.IP "\-\-disable\-eprt"
(FTP) Disable the use of the EPRT and LPRT commands when doing active FTP transfers.
Curl normally first attempts to use EPRT before using PORT, but with this
option, it uses PORT right away. EPRT is an extension to the original FTP
protocol, and does not work on all servers, but enables more functionality in
a better way than the traditional PORT command.

\fI\-\-eprt\fP can be used to explicitly enable EPRT again and \fI\-\-no\-eprt\fP is an alias
for \fI\-\-disable\-eprt\fP.

If the server is accessed using IPv6, this option has no effect as EPRT is
necessary then.

Disabling EPRT only changes the active behavior. If you want to switch to
passive mode you need to not use \fI\-P, \-\-ftp\-port\fP or force it with \fI\-\-ftp\-pasv\fP.

Providing --disable-eprt multiple times has no extra effect.
Disable it again with \-\-no-disable-eprt.

Example:
.nf
 curl --disable-eprt ftp://example.com/
.fi

See also \fI\-\-disable\-epsv\fP and \fI-P, \-\-ftp\-port\fP.
.IP "\-\-disable\-epsv"
(FTP) Disable the use of the EPSV command when doing passive FTP transfers. Curl
normally first attempts to use EPSV before PASV, but with this option, it does
not try EPSV.

\fI\-\-epsv\fP can be used to explicitly enable EPSV again and \fI\-\-no\-epsv\fP is an alias
for \fI\-\-disable\-epsv\fP.

If the server is an IPv6 host, this option has no effect as EPSV is necessary
then.

Disabling EPSV only changes the passive behavior. If you want to switch to
active mode you need to use \fI\-P, \-\-ftp\-port\fP.

Providing --disable-epsv multiple times has no extra effect.
Disable it again with \-\-no-disable-epsv.

Example:
.nf
 curl --disable-epsv ftp://example.com/
.fi

See also \fI\-\-disable\-eprt\fP and \fI-P, \-\-ftp\-port\fP.
.IP "\-\-disallow\-username\-in\-url"
Exit with error if passed a URL containing a username. Probably most useful
when the URL is being provided at runtime or similar.

Providing --disallow-username-in-url multiple times has no extra effect.
Disable it again with \-\-no-disallow-username-in-url.

Example:
.nf
 curl --disallow-username-in-url https://example.com
.fi

Added in 7.61.0. See also \fI\-\-proto\fP.
.IP "\-\-dns\-interface <interface>"
(DNS) Send outgoing DNS requests through the given interface. This option is a
counterpart to \fI\-\-interface\fP (which does not affect DNS). The supplied string
must be an interface name (not an address).

If --dns-interface is provided several times, the last set value is used.

Example:
.nf
 curl --dns-interface eth0 https://example.com
.fi

\fI\-\-dns\-interface\fP requires that libcurl is built to support c-ares.
See also \fI\-\-dns\-ipv4\-addr\fP and \fI\-\-dns\-ipv6\-addr\fP.
.IP "\-\-dns\-ipv4\-addr <address>"
(DNS) Bind to a specific IP address when making IPv4 DNS requests, so that the DNS
requests originate from this address. The argument should be a single IPv4
address.

If --dns-ipv4-addr is provided several times, the last set value is used.

Example:
.nf
 curl --dns-ipv4-addr 10.1.2.3 https://example.com
.fi

\fI\-\-dns\-ipv4\-addr\fP requires that libcurl is built to support c-ares.
See also \fI\-\-dns\-interface\fP and \fI\-\-dns\-ipv6\-addr\fP.
.IP "\-\-dns\-ipv6\-addr <address>"
(DNS) Bind to a specific IP address when making IPv6 DNS requests, so that the DNS
requests originate from this address. The argument should be a single IPv6
address.

If --dns-ipv6-addr is provided several times, the last set value is used.

Example:
.nf
 curl --dns-ipv6-addr 2a04:4e42::561 https://example.com
.fi

\fI\-\-dns\-ipv6\-addr\fP requires that libcurl is built to support c-ares.
See also \fI\-\-dns\-interface\fP and \fI\-\-dns\-ipv4\-addr\fP.
.IP "\-\-dns\-servers <addresses>"
(DNS) Set the list of DNS servers to be used instead of the system default. The list
of IP addresses should be separated with commas. Port numbers may also
optionally be given, appended to the IP address separated with a colon.

If --dns-servers is provided several times, the last set value is used.

Examples:
.nf
 curl --dns-servers 192.168.0.1,192.168.0.2 https://example.com
 curl --dns-servers 10.0.0.1:53 https://example.com
.fi

\fI\-\-dns\-servers\fP requires that libcurl is built to support c-ares.
See also \fI\-\-dns\-interface\fP and \fI\-\-dns\-ipv4\-addr\fP.
.IP "\-\-doh\-cert\-status"
Same as \fI\-\-cert\-status\fP but used for DoH (DNS\-over\-HTTPS).

Verifies the status of the DoH servers\(aq certificate by using the Certificate
Status Request (aka. OCSP stapling) TLS extension.

If this option is enabled and the DoH server sends an invalid (e.g. expired)
response, if the response suggests that the server certificate has been
revoked, or no response at all is received, the verification fails.

This support is currently only implemented in the OpenSSL and GnuTLS backends.

Providing --doh-cert-status multiple times has no extra effect.
Disable it again with \-\-no-doh-cert-status.

Example:
.nf
 curl --doh-cert-status --doh-url https://doh.example https://example.com
.fi

Added in 7.76.0. See also \fI\-\-doh\-insecure\fP.
.IP "\-\-doh\-insecure"
By default, every connection curl makes to a DoH server is verified to be
secure before the transfer takes place. This option tells curl to skip the
verification step and proceed without checking.

\fBWARNING\fP: using this option makes the DoH transfer and name resolution
insecure.

This option is equivalent to \fI\-k, \-\-insecure\fP and \fI\-\-proxy\-insecure\fP but used for DoH
(DNS\-over\-HTTPS) only.

Providing --doh-insecure multiple times has no extra effect.
Disable it again with \-\-no-doh-insecure.

Example:
.nf
 curl --doh-insecure --doh-url https://doh.example https://example.com
.fi

Added in 7.76.0. See also \fI\-\-doh\-url\fP, \fI-k, \-\-insecure\fP and \fI\-\-proxy\-insecure\fP.
.IP "\-\-doh\-url <URL>"
Specifies which DNS\-over\-HTTPS (DoH) server to use to resolve hostnames,
instead of using the default name resolver mechanism. The URL must be HTTPS.

Some SSL options that you set for your transfer also applies to DoH since the
name lookups take place over SSL. However, the certificate verification
settings are not inherited but are controlled separately via \fI\-\-doh\-insecure\fP
and \fI\-\-doh\-cert\-status\fP.

This option is unset if an empty string "" is used as the URL.
(Added in 7.85.0)

If --doh-url is provided several times, the last set value is used.

Example:
.nf
 curl --doh-url https://doh.example https://example.com
.fi

Added in 7.62.0. See also \fI\-\-doh\-insecure\fP.
.IP "\-D, \-\-dump\-header <filename>"
(HTTP FTP) Write the received protocol headers to the specified file. If no headers are
received, the use of this option creates an empty file. Specify "\-" as file
name (a single minus) to have it written to stdout.

When used in FTP, the FTP server response lines are considered being "headers"
and thus are saved there.

Having multiple transfers in one set of operations (i.e. the URLs in one
\fI\-:, \-\-next\fP clause), appends them to the same file, separated by a blank line.

If --dump-header is provided several times, the last set value is used.

Examples:
.nf
 curl --dump-header store.txt https://example.com
 curl --dump-header - https://example.com -o save
.fi

See also \fI-o, \-\-output\fP.
.IP "\-\-ech <config>"
(HTTPS) Specifies how to do ECH (Encrypted Client Hello).

The values allowed for <config> can be:
.RS
.IP false
Do not attempt ECH
.IP grease
Send a GREASE ECH extension
.IP true
Attempt ECH if possible, but do not fail if ECH is not attempted.
(The connection fails if ECH is attempted but fails.)
.IP hard
Attempt ECH and fail if that is not possible.
ECH only works with TLS 1.3 and also requires using
DoH or providing an ECHConfigList on the command line.
.IP ecl:<b64val>
A base64 encoded ECHConfigList that is used for ECH.
.IP pn:<name>
A name to use to over\-ride the "public_name" field of an ECHConfigList
(only available with OpenSSL TLS support)
.IP Errors
Most errors cause error
\fICURLE_ECH_REQUIRED\fP (101).
.RE
.IP

If --ech is provided several times, the last set value is used.

Example:
.nf
 curl --ech true https://example.com
.fi

Added in 8.8.0. See also \fI\-\-doh\-url\fP.
.IP "\-\-egd\-file <file>"
(TLS) Deprecated option (added in 7.84.0). Prior to that it only had an effect on
curl if built to use old versions of OpenSSL.

Specify the path name to the Entropy Gathering Daemon socket. The socket is
used to seed the random engine for SSL connections.

If --egd-file is provided several times, the last set value is used.

Example:
.nf
 curl --egd-file /random/here https://example.com
.fi

See also \fI\-\-random\-file\fP.
.IP "\-\-engine <name>"
(TLS) Select the OpenSSL crypto engine to use for cipher operations. Use \fI\-\-engine\fP
list to print a list of build\-time supported engines. Note that not all (and
possibly none) of the engines may be available at runtime.

If --engine is provided several times, the last set value is used.

Example:
.nf
 curl --engine flavor https://example.com
.fi

See also \fI\-\-ciphers\fP and \fI\-\-curves\fP.
.IP "\-\-etag\-compare <file>"
(HTTP) Make a conditional HTTP request for the specific ETag read from the given file
by sending a custom If\-None\-Match header using the stored ETag.

For correct results, make sure that the specified file contains only a single
line with the desired ETag. An empty file is parsed as an empty ETag.

Use the option \fI\-\-etag\-save\fP to first save the ETag from a response, and then
use this option to compare against the saved ETag in a subsequent request.

If --etag-compare is provided several times, the last set value is used.

Example:
.nf
 curl --etag-compare etag.txt https://example.com
.fi

Added in 7.68.0. See also \fI\-\-etag\-save\fP and \fI-z, \-\-time\-cond\fP.
.IP "\-\-etag\-save <file>"
(HTTP) Save an HTTP ETag to the specified file. An ETag is a caching related header,
usually returned in a response.

If no ETag is sent by the server, an empty file is created.

If --etag-save is provided several times, the last set value is used.

Example:
.nf
 curl --etag-save storetag.txt https://example.com
.fi

Added in 7.68.0. See also \fI\-\-etag\-compare\fP.
.IP "\-\-expect100\-timeout <seconds>"
(HTTP) Maximum time in seconds that you allow curl to wait for a 100\-continue
response when curl emits an Expects: 100\-continue header in its request. By
default curl waits one second. This option accepts decimal values. When curl
stops waiting, it continues as if a response was received.

The decimal value needs to provided using a dot (".") as decimal separator \-
not the local version even if it might be using another separator.

If --expect100-timeout is provided several times, the last set value is used.

Example:
.nf
 curl --expect100-timeout 2.5 -T file https://example.com
.fi

See also \fI\-\-connect\-timeout\fP.
.IP "\-f, \-\-fail"
(HTTP) Fail with error code 22 and with no response body output at all for HTTP
transfers returning HTTP response codes at 400 or greater.

In normal cases when an HTTP server fails to deliver a document, it returns a
body of text stating so (which often also describes why and more) and a 4xx
HTTP response code. This command line option prevents curl from outputting
that data and instead returns error 22 early. By default, curl does not
consider HTTP response codes to indicate failure.

To get both the error code and also save the content, use \fI\-\-fail\-with\-body\fP
instead.

This method is not fail\-safe and there are occasions where non\-successful
response codes slip through, especially when authentication is involved
(response codes 401 and 407).

Providing --fail multiple times has no extra effect.
Disable it again with \-\-no-fail.

Example:
.nf
 curl --fail https://example.com
.fi

This option is mutually exclusive with \fI\-\-fail\-with\-body\fP.
See also \fI\-\-fail\-with\-body\fP and \fI\-\-fail\-early\fP.
.IP "\-\-fail\-early"
Fail and exit on the first detected transfer error.

When curl is used to do multiple transfers on the command line, it attempts to
operate on each given URL, one by one. By default, it ignores errors if there
are more URLs given and the last URL\(aqs success determines the error code curl
returns. Early failures are "hidden" by subsequent successful transfers.

Using this option, curl instead returns an error on the first transfer that
fails, independent of the amount of URLs that are given on the command
line. This way, no transfer failures go undetected by scripts and similar.

This option does not imply \fI\-f, \-\-fail\fP, which causes transfers to fail due to the
server\(aqs HTTP status code. You can combine the two options, however note \fI\-f, \-\-fail\fP
is not global and is therefore contained by \fI\-:, \-\-next\fP.

This option is global and does not need to be specified for each use of --next.

Providing --fail-early multiple times has no extra effect.
Disable it again with \-\-no-fail-early.

Example:
.nf
 curl --fail-early https://example.com https://two.example
.fi

See also \fI-f, \-\-fail\fP and \fI\-\-fail\-with\-body\fP.
.IP "\-\-fail\-with\-body"
(HTTP) Return an error on server errors where the HTTP response code is 400 or
greater). In normal cases when an HTTP server fails to deliver a document, it
returns an HTML document stating so (which often also describes why and more).
This option allows curl to output and save that content but also to return
error 22.

This is an alternative option to \fI\-f, \-\-fail\fP which makes curl fail for the same
circumstances but without saving the content.

Providing --fail-with-body multiple times has no extra effect.
Disable it again with \-\-no-fail-with-body.

Example:
.nf
 curl --fail-with-body https://example.com
.fi

This option is mutually exclusive with \fI-f, \-\-fail\fP.
Added in 7.76.0. See also \fI-f, \-\-fail\fP and \fI\-\-fail\-early\fP.
.IP "\-\-false\-start"
(TLS) Use false start during the TLS handshake. False start is a mode where a TLS
client starts sending application data before verifying the server\(aqs Finished
message, thus saving a round trip when performing a full handshake.

This functionality is currently only implemented in the Secure Transport (on
iOS 7.0 or later, or OS X 10.9 or later) backend.

Providing --false-start multiple times has no extra effect.
Disable it again with \-\-no-false-start.

Example:
.nf
 curl --false-start https://example.com
.fi

See also \fI\-\-tcp\-fastopen\fP.
.IP "\-F, \-\-form <name=content>"
(HTTP SMTP IMAP) For the HTTP protocol family, emulate a filled\-in form in which a user has
pressed the submit button. This makes curl POST data using the Content\-Type
multipart/form\-data according to RFC 2388.

For SMTP and IMAP protocols, this composes a multipart mail message to
transmit.

This enables uploading of binary files etc. To force the \(aqcontent\(aq part to be
a file, prefix the filename with an @ sign. To just get the content part from
a file, prefix the filename with the symbol <. The difference between @ and
< is then that @ makes a file get attached in the post as a file upload,
while the < makes a text field and just get the contents for that text field
from a file.

Read content from stdin instead of a file by using a single "\-" as filename.
This goes for both @ and < constructs. When stdin is used, the contents is
buffered in memory first by curl to determine its size and allow a possible
resend. Defining a part\(aqs data from a named non\-regular file (such as a named
pipe or similar) is not subject to buffering and is instead read at
transmission time; since the full size is unknown before the transfer starts,
such data is sent as chunks by HTTP and rejected by IMAP.

Example: send an image to an HTTP server, where \(aqprofile\(aq is the name of the
form\-field to which the file \fBportrait.jpg\fP is the input:
.nf

curl \-F profile=@portrait.jpg https://example.com/upload.cgi
.fi

Example: send your name and shoe size in two text fields to the server:
.nf

curl \-F name=John \-F shoesize=11 https://example.com/
.fi

Example: send your essay in a text field to the server. Send it as a plain
text field, but get the contents for it from a local file:
.nf

curl \-F "story=<hugefile.txt" https://example.com/
.fi

You can also instruct curl what Content\-Type to use by using "type=", in a
manner similar to:
.nf

curl \-F "web=@index.html;type=text/html" example.com
.fi

or
.nf

curl \-F "name=daniel;type=text/foo" example.com
.fi

You can also explicitly change the name field of a file upload part by setting
filename=, like this:
.nf

curl \-F "file=@localfile;filename=nameinpost" example.com
.fi

If filename/path contains \(aq,\(aq or \(aq;\(aq, it must be quoted by double\-quotes like:
.nf

curl \-F "file=@\\"local,file\\";filename=\\"name;in;post\\"" example.com
.fi

or
.nf

curl \-F \(aqfile=@"local,file";filename="name;in;post"\(aq example.com
.fi

Note that if a filename/path is quoted by double\-quotes, any double\-quote
or backslash within the filename must be escaped by backslash.

Quoting must also be applied to non\-file data if it contains semicolons,
leading/trailing spaces or leading double quotes:
.nf

curl \-F \(aqcolors="red; green; blue";type=text/x\-myapp\(aq example.com
.fi

You can add custom headers to the field by setting headers=, like
.nf

curl \-F "submit=OK;headers=\\"X\-submit\-type: OK\\"" example.com
.fi

or
.nf

curl \-F "submit=OK;headers=@headerfile" example.com
.fi

The headers= keyword may appear more that once and above notes about quoting
apply. When headers are read from a file, Empty lines and lines starting
with \(aq#\(aq are comments and ignored; each header can be folded by splitting
between two words and starting the continuation line with a space; embedded
carriage\-returns and trailing spaces are stripped.
Here is an example of a header file contents:
.nf

# This file contain two headers.
X\-header\-1: this is a header

# The following header is folded.
X\-header\-2: this is
 another header
.fi

To support sending multipart mail messages, the syntax is extended as follows:

- name can be omitted: the equal sign is the first character of the argument,

- if data starts with \(aq(\(aq, this signals to start a new multipart: it can be
followed by a content type specification.

- a multipart can be terminated with a \(aq=)\(aq argument.

Example: the following command sends an SMTP mime email consisting in an
inline part in two alternative formats: plain text and HTML. It attaches a
text file:
.nf

curl \-F \(aq=(;type=multipart/alternative\(aq \\
     \-F \(aq=plain text message\(aq \\
     \-F \(aq= <body>HTML message</body>;type=text/html\(aq \\
     \-F \(aq=)\(aq \-F \(aq=@textfile.txt\(aq ...  smtp://example.com
.fi

Data can be encoded for transfer using encoder=. Available encodings are
\fIbinary\fP and \fI8bit\fP that do nothing else than adding the corresponding
Content\-Transfer\-Encoding header, \fI7bit\fP that only rejects 8\-bit characters
with a transfer error, \fIquoted\-printable\fP and \fIbase64\fP that encodes data
according to the corresponding schemes, limiting lines length to 76
characters.

Example: send multipart mail with a quoted\-printable text message and a
base64 attached file:
.nf

curl \-F \(aq=text message;encoder=quoted\-printable\(aq \\
     \-F \(aq=@localfile;encoder=base64\(aq ... smtp://example.com
.fi

See further examples and details in the MANUAL.

--form can be used several times in a command line

Example:
.nf
 curl --form "name=curl" --form "file=@loadthis" https://example.com
.fi

This option is mutually exclusive with \fI-d, \-\-data\fP, \fI-I, \-\-head\fP and \fI-T, \-\-upload\-file\fP.
See also \fI-d, \-\-data\fP, \fI\-\-form\-string\fP and \fI\-\-form\-escape\fP.
.IP "\-\-form\-escape"
(HTTP imap smtp) Pass on names of multipart form fields and files using backslash\-escaping
instead of percent\-encoding.

If --form-escape is provided several times, the last set value is used.

Example:
.nf
 curl --form-escape -F 'field\\name=curl' -F 'file=@load"this' https://example.com
.fi

Added in 7.81.0. See also \fI-F, \-\-form\fP.
.IP "\-\-form\-string <name=string>"
(HTTP SMTP IMAP) Similar to \fI\-F, \-\-form\fP except that the value string for the named parameter is used
literally. Leading @ and < characters, and the ";type=" string in the value
have no special meaning. Use this in preference to \fI\-F, \-\-form\fP if there is any
possibility that the string value may accidentally trigger the @ or <
features of \fI\-F, \-\-form\fP.

--form-string can be used several times in a command line

Example:
.nf
 curl --form-string "name=data" https://example.com
.fi

See also \fI-F, \-\-form\fP.
.IP "\-\-ftp\-account <data>"
(FTP) When an FTP server asks for "account data" after username and password has
been provided, this data is sent off using the ACCT command.

If --ftp-account is provided several times, the last set value is used.

Example:
.nf
 curl --ftp-account "mr.robot" ftp://example.com/
.fi

See also \fI-u, \-\-user\fP.
.IP "\-\-ftp\-alternative\-to\-user <command>"
(FTP) If authenticating with the USER and PASS commands fails, send this command.
When connecting to Tumbleweed\(aqs Secure Transport server over FTPS using a
client certificate, using "SITE AUTH" tells the server to retrieve the
username from the certificate.

If --ftp-alternative-to-user is provided several times, the last set value is used.

Example:
.nf
 curl --ftp-alternative-to-user "U53r" ftp://example.com
.fi

See also \fI\-\-ftp\-account\fP and \fI-u, \-\-user\fP.
.IP "\-\-ftp\-create\-dirs"
(FTP SFTP) When an FTP or SFTP URL/operation uses a path that does not currently exist on
the server, the standard behavior of curl is to fail. Using this option, curl
instead attempts to create missing directories.

Providing --ftp-create-dirs multiple times has no extra effect.
Disable it again with \-\-no-ftp-create-dirs.

Example:
.nf
 curl --ftp-create-dirs -T file ftp://example.com/remote/path/file
.fi

See also \fI\-\-create\-dirs\fP.
.IP "\-\-ftp\-method <method>"
(FTP) Control what method curl should use to reach a file on an FTP(S)
server. The method argument should be one of the following alternatives:
.RS
.IP multicwd
Do a single CWD operation for each path part in the given URL. For deep
hierarchies this means many commands. This is how RFC 1738 says it should be
done. This is the default but the slowest behavior.
.IP nocwd
Do no CWD at all. curl does SIZE, RETR, STOR etc and gives the full path to
the server for each of these commands. This is the fastest behavior.
.IP singlecwd
Do one CWD with the full target directory and then operate on the file
\&"normally" (like in the multicwd case). This is somewhat more standards
compliant than "nocwd" but without the full penalty of "multicwd".
.RE
.IP

If --ftp-method is provided several times, the last set value is used.

Examples:
.nf
 curl --ftp-method multicwd ftp://example.com/dir1/dir2/file
 curl --ftp-method nocwd ftp://example.com/dir1/dir2/file
 curl --ftp-method singlecwd ftp://example.com/dir1/dir2/file
.fi

See also \fI-l, \-\-list\-only\fP.
.IP "\-\-ftp\-pasv"
(FTP) Use passive mode for the data connection. Passive is the internal default
behavior, but using this option can be used to override a previous \fI\-P, \-\-ftp\-port\fP
option.

Reversing an enforced passive really is not doable but you must then instead
enforce the correct \fI\-P, \-\-ftp\-port\fP again.

Passive mode means that curl tries the EPSV command first and then PASV,
unless \fI\-\-disable\-epsv\fP is used.

Providing --ftp-pasv multiple times has no extra effect.
Disable it again with \-\-no-ftp-pasv.

Example:
.nf
 curl --ftp-pasv ftp://example.com/
.fi

See also \fI\-\-disable\-epsv\fP.
.IP "\-P, \-\-ftp\-port <address>"
(FTP) Reverses the default initiator/listener roles when connecting with FTP. This
option makes curl use active mode. curl then commands the server to connect
back to the client\(aqs specified address and port, while passive mode asks the
server to setup an IP address and port for it to connect to. <address>
should be one of:
.RS
.IP interface
e.g. \fBeth0\fP to specify which interface\(aqs IP address you want to use (Unix only)
.IP "IP address"
e.g. \fB192.168.10.1\fP to specify the exact IP address
.IP hostname
e.g. \fBmy.host.domain\fP to specify the machine
.IP -
make curl pick the same IP address that is already used for the control
connection. This is the recommended choice.
.RE
.IP
Disable the use of PORT with \fI\-\-ftp\-pasv\fP. Disable the attempt to use the EPRT
command instead of PORT by using \fI\-\-disable\-eprt\fP. EPRT is really PORT++.

You can also append ":[start]\-[end]" to the right of the address, to tell
curl what TCP port range to use. That means you specify a port range, from a
lower to a higher number. A single number works as well, but do note that it
increases the risk of failure since the port may not be available.


If --ftp-port is provided several times, the last set value is used.

Examples:
.nf
 curl -P - ftp:/example.com
 curl -P eth0 ftp:/example.com
 curl -P 192.168.0.2 ftp:/example.com
.fi

See also \fI\-\-ftp\-pasv\fP and \fI\-\-disable\-eprt\fP.
.IP "\-\-ftp\-pret"
(FTP) Send a PRET command before PASV (and EPSV). Certain FTP servers, mainly
drftpd, require this non\-standard command for directory listings as well as up
and downloads in PASV mode.

Providing --ftp-pret multiple times has no extra effect.
Disable it again with \-\-no-ftp-pret.

Example:
.nf
 curl --ftp-pret ftp://example.com/
.fi

See also \fI-P, \-\-ftp\-port\fP and \fI\-\-ftp\-pasv\fP.
.IP "\-\-ftp\-skip\-pasv\-ip"
(FTP) Do not use the IP address the server suggests in its response to curl\(aqs PASV
command when curl connects the data connection. Instead curl reuses the same
IP address it already uses for the control connection.

This option is enabled by default (added in 7.74.0).

This option has no effect if PORT, EPRT or EPSV is used instead of PASV.

Providing --ftp-skip-pasv-ip multiple times has no extra effect.
Disable it again with \-\-no-ftp-skip-pasv-ip.

Example:
.nf
 curl --ftp-skip-pasv-ip ftp://example.com/
.fi

See also \fI\-\-ftp\-pasv\fP.
.IP "\-\-ftp\-ssl\-ccc"
(FTP) Use CCC (Clear Command Channel) Shuts down the SSL/TLS layer after
authenticating. The rest of the control channel communication is be
unencrypted. This allows NAT routers to follow the FTP transaction. The
default mode is passive.

Providing --ftp-ssl-ccc multiple times has no extra effect.
Disable it again with \-\-no-ftp-ssl-ccc.

Example:
.nf
 curl --ftp-ssl-ccc ftps://example.com/
.fi

See also \fI\-\-ssl\fP and \fI\-\-ftp\-ssl\-ccc\-mode\fP.
.IP "\-\-ftp\-ssl\-ccc\-mode <active/passive>"
(FTP) Sets the CCC mode. The passive mode does not initiate the shutdown, but
instead waits for the server to do it, and does not reply to the shutdown from
the server. The active mode initiates the shutdown and waits for a reply from
the server.

Providing --ftp-ssl-ccc-mode multiple times has no extra effect.
Disable it again with \-\-no-ftp-ssl-ccc-mode.

Example:
.nf
 curl --ftp-ssl-ccc-mode active --ftp-ssl-ccc ftps://example.com/
.fi

See also \fI\-\-ftp\-ssl\-ccc\fP.
.IP "\-\-ftp\-ssl\-control"
(FTP) Require SSL/TLS for the FTP login, clear for transfer. Allows secure
authentication, but non\-encrypted data transfers for efficiency. Fails the
transfer if the server does not support SSL/TLS.

Providing --ftp-ssl-control multiple times has no extra effect.
Disable it again with \-\-no-ftp-ssl-control.

Example:
.nf
 curl --ftp-ssl-control ftp://example.com
.fi

See also \fI\-\-ssl\fP.
.IP "\-G, \-\-get"
(HTTP) When used, this option makes all data specified with \fI\-d, \-\-data\fP, \fI\-\-data\-binary\fP or
\fI\-\-data\-urlencode\fP to be used in an HTTP GET request instead of the POST request
that otherwise would be used. curl appends the provided data to the URL as a
query string.

If used in combination with \fI\-I, \-\-head\fP, the POST data is instead appended to the
URL with a HEAD request.

Providing --get multiple times has no extra effect.
Disable it again with \-\-no-get.

Examples:
.nf
 curl --get https://example.com
 curl --get -d "tool=curl" -d "age=old" https://example.com
 curl --get -I -d "tool=curl" https://example.com
.fi

See also \fI-d, \-\-data\fP and \fI-X, \-\-request\fP.
.IP "\-g, \-\-globoff"
Switch off the URL globbing function. When you set this option, you can
specify URLs that contain the letters {}[] without having curl itself
interpret them. Note that these letters are not normal legal URL contents but
they should be encoded according to the URI standard.

Providing --globoff multiple times has no extra effect.
Disable it again with \-\-no-globoff.

Example:
.nf
 curl -g "https://example.com/{[]}}}}"
.fi

See also \fI-K, \-\-config\fP and \fI-q, \-\-disable\fP.
.IP "\-\-happy\-eyeballs\-timeout\-ms <ms>"
Happy Eyeballs is an algorithm that attempts to connect to both IPv4 and IPv6
addresses for dual\-stack hosts, giving IPv6 a head\-start of the specified
number of milliseconds. If the IPv6 address cannot be connected to within that
time, then a connection attempt is made to the IPv4 address in parallel. The
first connection to be established is the one that is used.

The range of suggested useful values is limited. Happy Eyeballs RFC 6555 says
\&"It is RECOMMENDED that connection attempts be paced 150\-250 ms apart to
balance human factors against network load." libcurl currently defaults to
200 ms. Firefox and Chrome currently default to 300 ms.

If --happy-eyeballs-timeout-ms is provided several times, the last set value is used.

Example:
.nf
 curl --happy-eyeballs-timeout-ms 500 https://example.com
.fi

See also \fI-m, \-\-max\-time\fP and \fI\-\-connect\-timeout\fP.
.IP "\-\-haproxy\-clientip <ip>"
(HTTP) Sets a client IP in HAProxy PROXY protocol v1 header at the beginning of the
connection.

For valid requests, IPv4 addresses must be indicated as a series of exactly
4 integers in the range [0..255] inclusive written in decimal representation
separated by exactly one dot between each other. Heading zeroes are not
permitted in front of numbers in order to avoid any possible confusion
with octal numbers. IPv6 addresses must be indicated as series of 4 hexadecimal
digits (upper or lower case) delimited by colons between each other, with the
acceptance of one double colon sequence to replace the largest acceptable range
of consecutive zeroes. The total number of decoded bits must exactly be 128.

Otherwise, any string can be accepted for the client IP and get sent.

It replaces \fI\-\-haproxy\-protocol\fP if used, it is not necessary to specify both flags.

If --haproxy-clientip is provided several times, the last set value is used.

Example:
.nf
 curl --haproxy-clientip $IP
.fi

Added in 8.2.0. See also \fI-x, \-\-proxy\fP.
.IP "\-\-haproxy\-protocol"
(HTTP) Send a HAProxy PROXY protocol v1 header at the beginning of the connection.
This is used by some load balancers and reverse proxies to indicate the
client\(aqs true IP address and port.

This option is primarily useful when sending test requests to a service that
expects this header.

Providing --haproxy-protocol multiple times has no extra effect.
Disable it again with \-\-no-haproxy-protocol.

Example:
.nf
 curl --haproxy-protocol https://example.com
.fi

Added in 7.60.0. See also \fI-x, \-\-proxy\fP.
.IP "\-I, \-\-head"
(HTTP FTP FILE) Fetch the headers only! HTTP\-servers feature the command HEAD which this uses
to get nothing but the header of a document. When used on an FTP or FILE file,
curl displays the file size and last modification time only.

Providing --head multiple times has no extra effect.
Disable it again with \-\-no-head.

Example:
.nf
 curl -I https://example.com
.fi

See also \fI-G, \-\-get\fP, \fI-v, \-\-verbose\fP and \fI\-\-trace\-ascii\fP.
.IP "\-H, \-\-header <header/@file>"
(HTTP IMAP SMTP) Extra header to include in information sent. When used within an HTTP request,
it is added to the regular request headers.

For an IMAP or SMTP MIME uploaded mail built with \fI\-F, \-\-form\fP options, it is
prepended to the resulting MIME document, effectively including it at the mail
global level. It does not affect raw uploaded mails.

You may specify any number of extra headers. Note that if you should add a
custom header that has the same name as one of the internal ones curl would
use, your externally set header is used instead of the internal one. This
allows you to make even trickier stuff than curl would normally do. You should
not replace internally set headers without knowing perfectly well what you are
doing. Remove an internal header by giving a replacement without content on
the right side of the colon, as in: \-H "Host:". If you send the custom header
with no\-value then its header must be terminated with a semicolon, such as \-H
\&"X\-Custom\-Header;" to send "X\-Custom\-Header:".

curl makes sure that each header you add/replace is sent with the proper
end\-of\-line marker, you should thus \fBnot\fP add that as a part of the header
content: do not add newlines or carriage returns, they only mess things up for
you. curl passes on the verbatim string you give it without any filter or
other safe guards. That includes white space and control characters.

This option can take an argument in @filename style, which then adds a header
for each line in the input file. Using @\- makes curl read the header file from
stdin.

Please note that most anti\-spam utilities check the presence and value of
several MIME mail headers: these are "From:", "To:", "Date:" and "Subject:"
among others and should be added with this option.

You need \fI\-\-proxy\-header\fP to send custom headers intended for an HTTP proxy.


Passing on a "Transfer\-Encoding: chunked" header when doing an HTTP request
with a request body, makes curl send the data using chunked encoding.

\fBWARNING\fP: headers set with this option are set in all HTTP requests \- even
after redirects are followed, like when told with \fI\-L, \-\-location\fP. This can lead to
the header being sent to other hosts than the original host, so sensitive
headers should be used with caution combined with following redirects.

--header can be used several times in a command line

Examples:
.nf
 curl -H "X-First-Name: Joe" https://example.com
 curl -H "User-Agent: yes-please/2000" https://example.com
 curl -H "Host:" https://example.com
 curl -H @headers.txt https://example.com
.fi

See also \fI-A, \-\-user\-agent\fP and \fI-e, \-\-referer\fP.
.IP "\-h, \-\-help <category>"
Usage help. List all curl command line options within the given \fBcategory\fP.

If no argument is provided, curl displays the most important command line
arguments.

For category \fBall\fP, curl displays help for all options.

If \fBcategory\fP is specified, curl displays all available help categories.

Example:
.nf
 curl --help all
.fi

See also \fI-v, \-\-verbose\fP.
.IP "\-\-hostpubmd5 <md5>"
(SFTP SCP) Pass a string containing 32 hexadecimal digits. The string should be the 128
bit \fBMD5\fP checksum of the remote host\(aqs public key, curl refuses the
connection with the host unless the checksums match.

If --hostpubmd5 is provided several times, the last set value is used.

Example:
.nf
 curl --hostpubmd5 e5c1c49020640a5ab0f2034854c321a8 sftp://example.com/
.fi

See also \fI\-\-hostpubsha256\fP.
.IP "\-\-hostpubsha256 <sha256>"
(SFTP SCP) Pass a string containing a Base64\-encoded SHA256 hash of the remote host\(aqs
public key. Curl refuses the connection with the host unless the hashes match.

This feature requires libcurl to be built with libssh2 and does not work with
other SSH backends.

If --hostpubsha256 is provided several times, the last set value is used.

Example:
.nf
 curl --hostpubsha256 NDVkMTQxMGQ1ODdmMjQ3MjczYjAyOTY5MmRkMjVmNDQ= sftp://example.com/
.fi

Added in 7.80.0. See also \fI\-\-hostpubmd5\fP.
.IP "\-\-hsts <filename>"
(HTTPS) Enable HSTS for the transfer. If the filename points to an existing HSTS cache
file, that is used. After a completed transfer, the cache is saved to the
filename again if it has been modified.

If curl is told to use HTTP:// for a transfer involving a hostname that exists
in the HSTS cache, it upgrades the transfer to use HTTPS. Each HSTS cache
entry has an individual life time after which the upgrade is no longer
performed.

Specify a "" filename (zero length) to avoid loading/saving and make curl just
handle HSTS in memory.

If this option is used several times, curl loads contents from all the
files but the last one is used for saving.

--hsts can be used several times in a command line

Example:
.nf
 curl --hsts cache.txt https://example.com
.fi

Added in 7.74.0. See also \fI\-\-proto\fP.
.IP "\-\-http0.9"
(HTTP) Accept an HTTP version 0.9 response.

HTTP/0.9 is a response without headers and therefore you can also connect with
this to non\-HTTP servers and still get a response since curl simply
transparently downgrades \- if allowed.

HTTP/0.9 is disabled by default (added in 7.66.0)

Providing --http0.9 multiple times has no extra effect.
Disable it again with \-\-no-http0.9.

Example:
.nf
 curl --http0.9 https://example.com
.fi

Added in 7.64.0. See also \fI\-\-http1.1\fP, \fI\-\-http2\fP and \fI\-\-http3\fP.
.IP "\-0, \-\-http1.0"
(HTTP) Use HTTP version 1.0 instead of using its internally preferred HTTP version.

Providing --http1.0 multiple times has no extra effect.

Example:
.nf
 curl --http1.0 https://example.com
.fi

This option is mutually exclusive with \fI\-\-http1.1\fP, \fI\-\-http2\fP, \fI\-\-http2\-prior\-knowledge\fP and \fI\-\-http3\fP.
See also \fI\-\-http0.9\fP and \fI\-\-http1.1\fP.
.IP "\-\-http1.1"
(HTTP) Use HTTP version 1.1. This is the default with HTTP:// URLs.

Providing --http1.1 multiple times has no extra effect.

Example:
.nf
 curl --http1.1 https://example.com
.fi

This option is mutually exclusive with \fI\-\-http1.0\fP, \fI\-\-http2\fP, \fI\-\-http2\-prior\-knowledge\fP and \fI\-\-http3\fP.
See also \fI\-\-http1.0\fP and \fI\-\-http0.9\fP.
.IP "\-\-http2"
(HTTP) Use HTTP/2.

For HTTPS, this means curl negotiates HTTP/2 in the TLS handshake. curl does
this by default.

For HTTP, this means curl attempts to upgrade the request to HTTP/2 using the
Upgrade: request header.

When curl uses HTTP/2 over HTTPS, it does not itself insist on TLS 1.2 or
higher even though that is required by the specification. A user can add this
version requirement with \fI\-\-tlsv1.2\fP.

Providing --http2 multiple times has no extra effect.

Example:
.nf
 curl --http2 https://example.com
.fi

\fI\-\-http2\fP requires that libcurl is built to support HTTP/2.
This option is mutually exclusive with \fI\-\-http1.1\fP, \fI\-\-http1.0\fP, \fI\-\-http2\-prior\-knowledge\fP and \fI\-\-http3\fP.
See also \fI\-\-http1.1\fP, \fI\-\-http3\fP and \fI\-\-no\-alpn\fP.
.IP "\-\-http2\-prior\-knowledge"
(HTTP) Issue a non\-TLS HTTP requests using HTTP/2 directly without HTTP/1.1 Upgrade.
It requires prior knowledge that the server supports HTTP/2 straight away.
HTTPS requests still do HTTP/2 the standard way with negotiated protocol
version in the TLS handshake.

Providing --http2-prior-knowledge multiple times has no extra effect.
Disable it again with \-\-no-http2-prior-knowledge.

Example:
.nf
 curl --http2-prior-knowledge https://example.com
.fi

\fI\-\-http2\-prior\-knowledge\fP requires that libcurl is built to support HTTP/2.
This option is mutually exclusive with \fI\-\-http1.1\fP, \fI\-\-http1.0\fP, \fI\-\-http2\fP and \fI\-\-http3\fP.
See also \fI\-\-http2\fP and \fI\-\-http3\fP.
.IP "\-\-http3"
(HTTP) Attempt HTTP/3 to the host in the URL, but fallback to earlier HTTP versions
if the HTTP/3 connection establishment fails. HTTP/3 is only available for
HTTPS and not for HTTP URLs.

This option allows a user to avoid using the Alt\-Svc method of upgrading to
HTTP/3 when you know that the target speaks HTTP/3 on the given host and port.

When asked to use HTTP/3, curl issues a separate attempt to use older HTTP
versions with a slight delay, so if the HTTP/3 transfer fails or is slow, curl
still tries to proceed with an older HTTP version.

Use \fI\-\-http3\-only\fP for similar functionality \fIwithout\fP a fallback.

Providing --http3 multiple times has no extra effect.

Example:
.nf
 curl --http3 https://example.com
.fi

\fI\-\-http3\fP requires that libcurl is built to support HTTP/3.
This option is mutually exclusive with \fI\-\-http1.1\fP, \fI\-\-http1.0\fP, \fI\-\-http2\fP, \fI\-\-http2\-prior\-knowledge\fP and \fI\-\-http3\-only\fP.
Added in 7.66.0. See also \fI\-\-http1.1\fP and \fI\-\-http2\fP.
.IP "\-\-http3\-only"
(HTTP) Instructs curl to use HTTP/3 to the host in the URL, with no fallback to
earlier HTTP versions. HTTP/3 can only be used for HTTPS and not for HTTP
URLs. For HTTP, this option triggers an error.

This option allows a user to avoid using the Alt\-Svc method of upgrading to
HTTP/3 when you know that the target speaks HTTP/3 on the given host and port.

This option makes curl fail if a QUIC connection cannot be established, it
does not attempt any other HTTP versions on its own. Use \fI\-\-http3\fP for similar
functionality \fIwith\fP a fallback.

Providing --http3-only multiple times has no extra effect.

Example:
.nf
 curl --http3-only https://example.com
.fi

\fI\-\-http3\-only\fP requires that libcurl is built to support HTTP/3.
This option is mutually exclusive with \fI\-\-http1.1\fP, \fI\-\-http1.0\fP, \fI\-\-http2\fP, \fI\-\-http2\-prior\-knowledge\fP and \fI\-\-http3\fP.
Added in 7.88.0. See also \fI\-\-http1.1\fP, \fI\-\-http2\fP and \fI\-\-http3\fP.
.IP "\-\-ignore\-content\-length"
(FTP HTTP) For HTTP, Ignore the Content\-Length header. This is particularly useful for
servers running Apache 1.x, which reports incorrect Content\-Length for
files larger than 2 gigabytes.

For FTP, this makes curl skip the SIZE command to figure out the size before
downloading a file.

This option does not work for HTTP if libcurl was built to use hyper.

Providing --ignore-content-length multiple times has no extra effect.
Disable it again with \-\-no-ignore-content-length.

Example:
.nf
 curl --ignore-content-length https://example.com
.fi

See also \fI\-\-ftp\-skip\-pasv\-ip\fP.
.IP "\-i, \-\-include"
(HTTP FTP) Include response headers in the output. HTTP response headers can include
things like server name, cookies, date of the document, HTTP version and
more... With non\-HTTP protocols, the "headers" are other server communication.

To view the request headers, consider the \fI\-v, \-\-verbose\fP option.

Providing --include multiple times has no extra effect.
Disable it again with \-\-no-include.

Example:
.nf
 curl -i https://example.com
.fi

See also \fI-v, \-\-verbose\fP.
.IP "\-k, \-\-insecure"
(TLS SFTP SCP) By default, every secure connection curl makes is verified to be secure before
the transfer takes place. This option makes curl skip the verification step
and proceed without checking.

When this option is not used for protocols using TLS, curl verifies the
server\(aqs TLS certificate before it continues: that the certificate contains
the right name which matches the hostname used in the URL and that the
certificate has been signed by a CA certificate present in the cert store. See
this online resource for further details:
\fBhttps://curl.se/docs/sslcerts.html\fP

For SFTP and SCP, this option makes curl skip the \fIknown_hosts\fP verification.
\fIknown_hosts\fP is a file normally stored in the user\(aqs home directory in the
\&".ssh" subdirectory, which contains hostnames and their public keys.

\fBWARNING\fP: using this option makes the transfer insecure.

When curl uses secure protocols it trusts responses and allows for example
HSTS and Alt\-Svc information to be stored and used subsequently. Using
\fI\-k, \-\-insecure\fP can make curl trust and use such information from malicious
servers.

Providing --insecure multiple times has no extra effect.
Disable it again with \-\-no-insecure.

Example:
.nf
 curl --insecure https://example.com
.fi

See also \fI\-\-proxy\-insecure\fP, \fI\-\-cacert\fP and \fI\-\-capath\fP.
.IP "\-\-interface <name>"
Perform the operation using a specified interface. You can enter interface
name, IP address or hostname. If you prefer to be specific, you can use the
following special syntax:
.RS
.IP if!<name>
Interface name. If the provided name does not match an existing interface,
curl returns with error 45.
.IP host!<name>
IP address or hostname.
.IP ifhost!<interface>!<host>
Interface name and IP address or hostname. This syntax requires libcurl 8.9.0
or later.

If the provided name does not match an existing interface, curl returns with
error 45.
.RE
.IP
curl does not support using network interface names for this option on
Windows.

That name resolve operation if a hostname is provided does \fBnot\fP use
DNS\-over\-HTTPS even if \fI\-\-doh\-url\fP is set.

On Linux this option can be used to specify a \fBVRF\fP (Virtual Routing and
Forwarding) device, but the binary then needs to either have the
\fBCAP_NET_RAW\fP capability set or to be run as root.

If --interface is provided several times, the last set value is used.

Examples:
.nf
 curl --interface eth0 https://example.com
 curl --interface "host!10.0.0.1" https://example.com
 curl --interface "if!enp3s0" https://example.com
.fi

See also \fI\-\-dns\-interface\fP.
.IP "\-\-ip\-tos <string>"
(All) Set Type of Service (TOS) for IPv4 or Traffic Class for IPv6.

The values allowed for <string> can be a numeric value between 1 and 255
or one of the following:

CS0, CS1, CS2, CS3, CS4, CS5, CS6, CS7, AF11, AF12, AF13, AF21, AF22, AF23,
AF31, AF32, AF33, AF41, AF42, AF43, EF, VOICE\-ADMIT, ECT1, ECT0, CE, LE,
LOWCOST, LOWDELAY, THROUGHPUT, RELIABILITY, MINCOST

If --ip-tos is provided several times, the last set value is used.

Example:
.nf
 curl --ip-tos CS5 https://example.com
.fi

Added in 8.9.0. See also \fI\-\-tcp\-nodelay\fP and \fI\-\-vlan\-priority\fP.
.IP "\-\-ipfs\-gateway <URL>"
(IPFS) Specify which gateway to use for IPFS and IPNS URLs. Not specifying this
instead makes curl check if the IPFS_GATEWAY environment variable is set, or
if a "~/.ipfs/gateway" file holding the gateway URL exists.

If you run a local IPFS node, this gateway is by default available under
\&"http://localhost:8080". A full example URL would look like:
.nf

curl \--ipfs\-gateway http://localhost:8080 ipfs://bafybeigagd5nmnn2iys2f3doro7ydrevyr2mzarwidgadawmamiteydbzi
.fi

There are many public IPFS gateways. See for example:
https://ipfs.github.io/public\-gateway\-checker/

If you opt to go for a remote gateway you need to be aware that you completely
trust the gateway. This might be fine in local gateways that you host
yourself. With remote gateways there could potentially be malicious actors
returning you data that does not match the request you made, inspect or even
interfere with the request. You may not notice this when using curl. A
mitigation could be to go for a "trustless" gateway. This means you locally
verify that the data. Consult the docs page on trusted vs trustless:
https://docs.ipfs.tech/reference/http/gateway/#trusted\-vs\-trustless

If --ipfs-gateway is provided several times, the last set value is used.

Example:
.nf
 curl --ipfs-gateway https://example.com ipfs://
.fi

Added in 8.4.0. See also \fI-h, \-\-help\fP and \fI-M, \-\-manual\fP.
.IP "\-4, \-\-ipv4"
Use IPv4 addresses only when resolving hostnames, and not for example try
IPv6.

Providing --ipv4 multiple times has no extra effect.

Example:
.nf
 curl --ipv4 https://example.com
.fi

This option is mutually exclusive with \fI-6, \-\-ipv6\fP.
See also \fI\-\-http1.1\fP and \fI\-\-http2\fP.
.IP "\-6, \-\-ipv6"
Use IPv6 addresses only when resolving hostnames, and not for example try
IPv4.

Your resolver may respond to an IPv6\-only resolve request by returning IPv6
addresses that contain "mapped" IPv4 addresses for compatibility purposes.
macOS is known to do this.

Providing --ipv6 multiple times has no extra effect.

Example:
.nf
 curl --ipv6 https://example.com
.fi

This option is mutually exclusive with \fI-4, \-\-ipv4\fP.
See also \fI\-\-http1.1\fP and \fI\-\-http2\fP.
.IP "\-\-json <data>"
(HTTP) Sends the specified JSON data in a POST request to the HTTP server. \fI\-\-json\fP
works as a shortcut for passing on these three options:
.nf

-\-data [arg]
-\-header "Content\-Type: application/json"
-\-header "Accept: application/json"
.fi

There is \fBno verification\fP that the passed in data is actual JSON or that
the syntax is correct.

If you start the data with the letter @, the rest should be a filename to read
the data from, or a single dash (\-) if you want curl to read the data from
stdin. Posting data from a file named \(aqfoobar\(aq would thus be done with \fI\-\-json\fP
@foobar and to instead read the data from stdin, use \fI\-\-json\fP @\-.

If this option is used more than once on the same command line, the additional
data pieces are concatenated to the previous before sending.

The headers this option sets can be overridden with \fI\-H, \-\-header\fP as usual.

--json can be used several times in a command line

Examples:
.nf
 curl --json '{ "drink": "coffe" }' https://example.com
 curl --json '{ "drink":' --json ' "coffe" }' https://example.com
 curl --json @prepared https://example.com
 curl --json @- https://example.com < json.txt
.fi

This option is mutually exclusive with \fI-F, \-\-form\fP, \fI-I, \-\-head\fP and \fI-T, \-\-upload\-file\fP.
Added in 7.82.0. See also \fI\-\-data\-binary\fP and \fI\-\-data\-raw\fP.
.IP "\-j, \-\-junk\-session\-cookies"
(HTTP) When curl is told to read cookies from a given file, this option makes it
discard all "session cookies". This has the same effect as if a new session is
started. Typical browsers discard session cookies when they are closed down.

Providing --junk-session-cookies multiple times has no extra effect.
Disable it again with \-\-no-junk-session-cookies.

Example:
.nf
 curl --junk-session-cookies -b cookies.txt https://example.com
.fi

See also \fI-b, \-\-cookie\fP and \fI-c, \-\-cookie\-jar\fP.
.IP "\-\-keepalive\-cnt <integer>"
Set the maximum number of keepalive probes TCP should send but get no response
before dropping the connection. This option is usually used in conjunction
with \fI\-\-keepalive\-time\fP.

This option is supported on Linux, *BSD/macOS, Windows >=10.0.16299, Solaris
11.4, and recent AIX, HP\-UX and more. This option has no effect if
\fI\-\-no\-keepalive\fP is used.

If unspecified, the option defaults to 9.

If --keepalive-cnt is provided several times, the last set value is used.

Example:
.nf
 curl --keepalive-cnt 3 https://example.com
.fi

Added in 8.9.0. See also \fI\-\-keepalive\-time\fP and \fI\-\-no\-keepalive\fP.
.IP "\-\-keepalive\-time <seconds>"
Set the time a connection needs to remain idle before sending keepalive probes
and the time between individual keepalive probes. It is currently effective on
operating systems offering the "TCP_KEEPIDLE" and "TCP_KEEPINTVL" socket
options (meaning Linux, *BSD/macOS, Windows, Solaris, and recent AIX, HP\-UX and more).
Keepalive is used by the TCP stack to detect broken networks on idle connections.
The number of missed keepalive probes before declaring the connection down is OS
dependent and is commonly 8 (*BSD/macOS/AIX), 9 (Linux/AIX) or 5/10 (Windows), and
this number can be changed by specifying the curl option "keepalive\-cnt".
Note that this option has no effect if \fI\-\-no\-keepalive\fP is used.

If unspecified, the option defaults to 60 seconds.

If --keepalive-time is provided several times, the last set value is used.

Example:
.nf
 curl --keepalive-time 20 https://example.com
.fi

See also \fI\-\-no\-keepalive\fP, \fI\-\-keepalive\-cnt\fP and \fI-m, \-\-max\-time\fP.
.IP "\-\-key <key>"
(TLS SSH) Private key filename. Allows you to provide your private key in this separate
file. For SSH, if not specified, curl tries the following candidates in order:
\&"~/.ssh/id_rsa", "~/.ssh/id_dsa", "./id_rsa", "./id_dsa".

If curl is built against OpenSSL library, and the engine pkcs11 is available,
then a PKCS#11 URI (RFC 7512) can be used to specify a private key located in
a PKCS#11 device. A string beginning with "pkcs11:" is interpreted as a
PKCS#11 URI. If a PKCS#11 URI is provided, then the \fI\-\-engine\fP option is set as
\&"pkcs11" if none was provided and the \fI\-\-key\-type\fP option is set as "ENG" if
none was provided.

If curl is built against Secure Transport or Schannel then this option is
ignored for TLS protocols (HTTPS, etc). Those backends expect the private key
to be already present in the keychain or PKCS#12 file containing the
certificate.

If --key is provided several times, the last set value is used.

Example:
.nf
 curl --cert certificate --key here https://example.com
.fi

See also \fI\-\-key\-type\fP and \fI-E, \-\-cert\fP.
.IP "\-\-key\-type <type>"
(TLS) Private key file type. Specify which type your \fI\-\-key\fP provided private key
is. DER, PEM, and ENG are supported. If not specified, PEM is assumed.

If --key-type is provided several times, the last set value is used.

Example:
.nf
 curl --key-type DER --key here https://example.com
.fi

See also \fI\-\-key\fP.
.IP "\-\-krb <level>"
(FTP) Enable Kerberos authentication and use. The level must be entered and should
be one of \(aqclear\(aq, \(aqsafe\(aq, \(aqconfidential\(aq, or \(aqprivate\(aq. Should you use a
level that is not one of these, \(aqprivate\(aq is used.

If --krb is provided several times, the last set value is used.

Example:
.nf
 curl --krb clear ftp://example.com/
.fi

\fI\-\-krb\fP requires that libcurl is built to support Kerberos.
See also \fI\-\-delegation\fP and \fI\-\-ssl\fP.
.IP "\-\-libcurl <file>"
Append this option to any ordinary curl command line, and you get
libcurl\-using C source code written to the file that does the equivalent of
what your command\-line operation does!

This option is global and does not need to be specified for each use of --next.

If --libcurl is provided several times, the last set value is used.

Example:
.nf
 curl --libcurl client.c https://example.com
.fi

See also \fI-v, \-\-verbose\fP.
.IP "\-\-limit\-rate <speed>"
Specify the maximum transfer rate you want curl to use \- for both downloads
and uploads. This feature is useful if you have a limited pipe and you would
like your transfer not to use your entire bandwidth. To make it slower than it
otherwise would be.

The given speed is measured in bytes/second, unless a suffix is appended.
Appending \(aqk\(aq or \(aqK\(aq counts the number as kilobytes, \(aqm\(aq or \(aqM\(aq makes it
megabytes, while \(aqg\(aq or \(aqG\(aq makes it gigabytes. The suffixes (k, M, G, T, P)
are 1024 based. For example 1k is 1024. Examples: 200K, 3m and 1G.

The rate limiting logic works on averaging the transfer speed to no more than
the set threshold over a period of multiple seconds.

If you also use the \fI\-Y, \-\-speed\-limit\fP option, that option takes precedence and
might cripple the rate\-limiting slightly, to help keeping the speed\-limit
logic working.

If --limit-rate is provided several times, the last set value is used.

Examples:
.nf
 curl --limit-rate 100K https://example.com
 curl --limit-rate 1000 https://example.com
 curl --limit-rate 10M https://example.com
.fi

See also \fI\-\-rate\fP, \fI-Y, \-\-speed\-limit\fP and \fI-y, \-\-speed\-time\fP.
.IP "\-l, \-\-list\-only"
(FTP POP3 SFTP FILE) When listing an FTP directory, force a name\-only view. Maybe particularly
useful if the user wants to machine\-parse the contents of an FTP directory
since the normal directory view does not use a standard look or format. When
used like this, the option causes an NLST command to be sent to the server
instead of LIST.

Note: Some FTP servers list only files in their response to NLST; they do not
include sub\-directories and symbolic links.

When listing an SFTP directory, this switch forces a name\-only view, one per
line. This is especially useful if the user wants to machine\-parse the
contents of an SFTP directory since the normal directory view provides more
information than just filenames.

When retrieving a specific email from POP3, this switch forces a LIST command
to be performed instead of RETR. This is particularly useful if the user wants
to see if a specific message\-id exists on the server and what size it is.

For FILE, this option has no effect yet as directories are always listed in
this mode.

Note: When combined with \fI\-X, \-\-request\fP, this option can be used to send a UIDL
command instead, so the user may use the email\(aqs unique identifier rather than
its message\-id to make the request.

Providing --list-only multiple times has no extra effect.
Disable it again with \-\-no-list-only.

Example:
.nf
 curl --list-only ftp://example.com/dir/
.fi

See also \fI-Q, \-\-quote\fP and \fI-X, \-\-request\fP.
.IP "\-\-local\-port <range>"
Set a preferred single number or range (FROM\-TO) of local port numbers to use
for the connection(s). Note that port numbers by nature are a scarce resource
so setting this range to something too narrow might cause unnecessary
connection setup failures.

If --local-port is provided several times, the last set value is used.

Example:
.nf
 curl --local-port 1000-3000 https://example.com
.fi

See also \fI-g, \-\-globoff\fP.
.IP "\-L, \-\-location"
(HTTP) If the server reports that the requested page has moved to a different
location (indicated with a Location: header and a 3XX response code), this
option makes curl redo the request on the new place. If used together with
\fI\-i, \-\-include\fP or \fI\-I, \-\-head\fP, headers from all requested pages are shown.

When authentication is used, curl only sends its credentials to the initial
host. If a redirect takes curl to a different host, it does not get the
user+password pass on. See also \fI\-\-location\-trusted\fP on how to change this.

Limit the amount of redirects to follow by using the \fI\-\-max\-redirs\fP option.

When curl follows a redirect and if the request is a POST, it sends the
following request with a GET if the HTTP response was 301, 302, or 303. If the
response code was any other 3xx code, curl resends the following request using
the same unmodified method.

You can tell curl to not change POST requests to GET after a 30x response by
using the dedicated options for that: \fI\-\-post301\fP, \fI\-\-post302\fP and \fI\-\-post303\fP.

The method set with \fI\-X, \-\-request\fP overrides the method curl would otherwise select
to use.

Providing --location multiple times has no extra effect.
Disable it again with \-\-no-location.

Example:
.nf
 curl -L https://example.com
.fi

See also \fI\-\-resolve\fP and \fI\-\-alt\-svc\fP.
.IP "\-\-location\-trusted"
(HTTP) Like \fI\-L, \-\-location\fP, but allows sending the name + password to all hosts that the
site may redirect to. This may or may not introduce a security breach if the
site redirects you to a site to which you send your authentication info (which
is clear\-text in the case of HTTP Basic authentication).

Providing --location-trusted multiple times has no extra effect.
Disable it again with \-\-no-location-trusted.

Example:
.nf
 curl --location-trusted -u user:password https://example.com
.fi

See also \fI-u, \-\-user\fP.
.IP "\-\-login\-options <options>"
(IMAP LDAP POP3 SMTP) Specify the login options to use during server authentication.

You can use login options to specify protocol specific options that may be
used during authentication. At present only IMAP, POP3 and SMTP support login
options. For more information about login options please see RFC 2384,
RFC 5092 and the IETF draft
https://datatracker.ietf.org/doc/html/draft\-earhart\-url\-smtp\-00

Since 8.2.0, IMAP supports the login option "AUTH=+LOGIN". With this option,
curl uses the plain (not SASL) "LOGIN IMAP" command even if the server
advertises SASL authentication. Care should be taken in using this option, as
it sends your password over the network in plain text. This does not work if
the IMAP server disables the plain "LOGIN" (e.g. to prevent password
snooping).

If --login-options is provided several times, the last set value is used.

Example:
.nf
 curl --login-options 'AUTH=*' imap://example.com
.fi

See also \fI-u, \-\-user\fP.
.IP "\-\-mail\-auth <address>"
(SMTP) Specify a single address. This is used to specify the authentication address
(identity) of a submitted message that is being relayed to another server.

If --mail-auth is provided several times, the last set value is used.

Example:
.nf
 curl --mail-auth user@example.com -T mail smtp://example.com/
.fi

See also \fI\-\-mail\-rcpt\fP and \fI\-\-mail\-from\fP.
.IP "\-\-mail\-from <address>"
(SMTP) Specify a single address that the given mail should get sent from.

If --mail-from is provided several times, the last set value is used.

Example:
.nf
 curl --mail-from user@example.com -T mail smtp://example.com/
.fi

See also \fI\-\-mail\-rcpt\fP and \fI\-\-mail\-auth\fP.
.IP "\-\-mail\-rcpt <address>"
(SMTP) Specify a single email address, username or mailing list name. Repeat this
option several times to send to multiple recipients.

When performing an address verification (\fBVRFY\fP command), the recipient
should be specified as the username or username and domain (as per Section 3.5
of RFC 5321).

When performing a mailing list expand (EXPN command), the recipient should be
specified using the mailing list name, such as "Friends" or "London\-Office".


--mail-rcpt can be used several times in a command line

Example:
.nf
 curl --mail-rcpt user@example.net smtp://example.com
.fi

See also \fI\-\-mail\-rcpt\-allowfails\fP.
.IP "\-\-mail\-rcpt\-allowfails"
(SMTP) When sending data to multiple recipients, by default curl aborts SMTP
conversation if at least one of the recipients causes RCPT TO command to
return an error.

The default behavior can be changed by passing \fI\-\-mail\-rcpt\-allowfails\fP
command\-line option which makes curl ignore errors and proceed with the
remaining valid recipients.

If all recipients trigger RCPT TO failures and this flag is specified, curl
still aborts the SMTP conversation and returns the error received from to the
last RCPT TO command.

Providing --mail-rcpt-allowfails multiple times has no extra effect.
Disable it again with \-\-no-mail-rcpt-allowfails.

Example:
.nf
 curl --mail-rcpt-allowfails --mail-rcpt dest@example.com smtp://example.com
.fi

Added in 7.69.0. See also \fI\-\-mail\-rcpt\fP.
.IP "\-M, \-\-manual"
Manual. Display the huge help text.

Example:
.nf
 curl --manual
.fi

See also \fI-v, \-\-verbose\fP, \fI\-\-libcurl\fP and \fI\-\-trace\fP.
.IP "\-\-max\-filesize <bytes>"
(FTP HTTP MQTT) Specify the maximum size (in bytes) of a file to download. If the file
requested is larger than this value, the transfer does not start and curl
returns with exit code 63.

A size modifier may be used. For example, Appending \(aqk\(aq or \(aqK\(aq counts the
number as kilobytes, \(aqm\(aq or \(aqM\(aq makes it megabytes, while \(aqg\(aq or \(aqG\(aq makes it
gigabytes. Examples: 200K, 3m and 1G.

\fBNOTE\fP: before curl 8.4.0, when the file size is not known prior to
download, for such files this option has no effect even if the file transfer
ends up being larger than this given limit.

Starting with curl 8.4.0, this option aborts the transfer if it reaches the
threshold during transfer.

If --max-filesize is provided several times, the last set value is used.

Example:
.nf
 curl --max-filesize 100K https://example.com
.fi

See also \fI\-\-limit\-rate\fP.
.IP "\-\-max\-redirs <num>"
(HTTP) Set maximum number of redirections to follow. When \fI\-L, \-\-location\fP is used, to
prevent curl from following too many redirects, by default, the limit is
set to 50 redirects. Set this option to \-1 to make it unlimited.

If --max-redirs is provided several times, the last set value is used.

Example:
.nf
 curl --max-redirs 3 --location https://example.com
.fi

See also \fI-L, \-\-location\fP.
.IP "\-m, \-\-max\-time <seconds>"
Set maximum time in seconds that you allow each transfer to take. Prevents
your batch jobs from hanging for hours due to slow networks or links going
down. This option accepts decimal values.

If you enable retrying the transfer (\fI\-\-retry\fP) then the maximum time counter is
reset each time the transfer is retried. You can use \fI\-\-retry\-max\-time\fP to limit
the retry time.

The decimal value needs to provided using a dot (.) as decimal separator \- not
the local version even if it might be using another separator.

If --max-time is provided several times, the last set value is used.

Examples:
.nf
 curl --max-time 10 https://example.com
 curl --max-time 2.92 https://example.com
.fi

See also \fI\-\-connect\-timeout\fP and \fI\-\-retry\-max\-time\fP.
.IP "\-\-metalink"
This option was previously used to specify a Metalink resource. Metalink
support is disabled in curl for security reasons (added in 7.78.0).

If --metalink is provided several times, the last set value is used.

Example:
.nf
 curl --metalink file https://example.com
.fi

See also \fI-Z, \-\-parallel\fP.
.IP "\-\-mptcp"
Enables the use of Multipath TCP (MPTCP) for connections. MPTCP is an extension
to the standard TCP that allows multiple TCP streams over different network
paths between the same source and destination. This can enhance bandwidth and
improve reliability by using multiple paths simultaneously.

MPTCP is beneficial in networks where multiple paths exist between clients and
servers, such as mobile networks where a device may switch between WiFi and
cellular data or in wired networks with multiple Internet Service Providers.

This option is currently only supported on Linux starting from kernel 5.6. Only
TCP connections are modified, hence this option does not effect HTTP/3 (QUIC)
or UDP connections.

The server curl connects to must also support MPTCP. If not, the connection
seamlessly falls back to TCP.

Providing --mptcp multiple times has no extra effect.
Disable it again with \-\-no-mptcp.

Example:
.nf
 curl --mptcp https://example.com
.fi

Added in 8.9.0. See also \fI\-\-tcp\-fastopen\fP.
.IP "\-\-negotiate"
(HTTP) Enable Negotiate (SPNEGO) authentication.

This option requires a library built with GSS\-API or SSPI support. Use
\fI\-V, \-\-version\fP to see if your curl supports GSS\-API/SSPI or SPNEGO.

When using this option, you must also provide a fake \fI\-u, \-\-user\fP option to activate
the authentication code properly. Sending a \(aq\-u :\(aq is enough as the username
and password from the \fI\-u, \-\-user\fP option are not actually used.

Providing --negotiate multiple times has no extra effect.

Example:
.nf
 curl --negotiate -u : https://example.com
.fi

See also \fI\-\-basic\fP, \fI\-\-ntlm\fP, \fI\-\-anyauth\fP and \fI\-\-proxy\-negotiate\fP.
.IP "\-n, \-\-netrc"
Make curl scan the \fI.netrc\fP file in the user\(aqs home directory for login name
and password. This is typically used for FTP on Unix. If used with HTTP, curl
enables user authentication. See \fInetrc(5)\fP and \fIftp(1)\fP for details on the
file format. Curl does not complain if that file does not have the right
permissions (it should be neither world\- nor group\-readable). The environment
variable "HOME" is used to find the home directory.

On Windows two filenames in the home directory are checked: \fI.netrc\fP and
\fI_netrc\fP, preferring the former. Older versions on Windows checked for \fI_netrc\fP
only.

A quick and simple example of how to setup a \fI.netrc\fP to allow curl to FTP to
the machine host.domain.com with username \(aqmyself\(aq and password \(aqsecret\(aq could
look similar to:
.nf

machine host.domain.com
login myself
password secret
.fi

Providing --netrc multiple times has no extra effect.
Disable it again with \-\-no-netrc.

Example:
.nf
 curl --netrc https://example.com
.fi

This option is mutually exclusive with \fI\-\-netrc\-file\fP and \fI\-\-netrc\-optional\fP.
See also \fI\-\-netrc\-file\fP, \fI-K, \-\-config\fP and \fI-u, \-\-user\fP.
.IP "\-\-netrc\-file <filename>"
Set the netrc file to use. Similar to \fI\-n, \-\-netrc\fP, except that you also provide
the path (absolute or relative).

It abides by \fI\-\-netrc\-optional\fP if specified.

If --netrc-file is provided several times, the last set value is used.

Example:
.nf
 curl --netrc-file netrc https://example.com
.fi

This option is mutually exclusive with \fI-n, \-\-netrc\fP.
See also \fI-n, \-\-netrc\fP, \fI-u, \-\-user\fP and \fI-K, \-\-config\fP.
.IP "\-\-netrc\-optional"
Similar to \fI\-n, \-\-netrc\fP, but this option makes the .netrc usage \fBoptional\fP
and not mandatory as the \fI\-n, \-\-netrc\fP option does.

Providing --netrc-optional multiple times has no extra effect.
Disable it again with \-\-no-netrc-optional.

Example:
.nf
 curl --netrc-optional https://example.com
.fi

This option is mutually exclusive with \fI-n, \-\-netrc\fP.
See also \fI\-\-netrc\-file\fP.
.IP "\-:, \-\-next"
Use a separate operation for the following URL and associated options. This
allows you to send several URL requests, each with their own specific options,
for example, such as different usernames or custom requests for each.

\fI\-:, \-\-next\fP resets all local options and only global ones have their values survive
over to the operation following the \fI\-:, \-\-next\fP instruction. Global options include
\fI\-v, \-\-verbose\fP, \fI\-\-trace\fP, \fI\-\-trace\-ascii\fP and \fI\-\-fail\-early\fP.

For example, you can do both a GET and a POST in a single command line:
.nf

curl www1.example.com \--next \-d postthis www2.example.com
.fi

--next can be used several times in a command line

Examples:
.nf
 curl https://example.com --next -d postthis www2.example.com
 curl -I https://example.com --next https://example.net/
.fi

See also \fI-Z, \-\-parallel\fP and \fI-K, \-\-config\fP.
.IP "\-\-no\-alpn"
(HTTPS) Disable the ALPN TLS extension. ALPN is enabled by default if libcurl was built
with an SSL library that supports ALPN. ALPN is used by a libcurl that supports
HTTP/2 to negotiate HTTP/2 support with the server during https sessions.

Note that this is the negated option name documented. You can use \fI\-\-alpn\fP to
enable ALPN.

Providing --no-alpn multiple times has no extra effect.
Disable it again with \-\-alpn.

Example:
.nf
 curl --no-alpn https://example.com
.fi

\fI\-\-no\-alpn\fP requires that libcurl is built to support TLS.
See also \fI\-\-no\-npn\fP and \fI\-\-http2\fP.
.IP "\-N, \-\-no\-buffer"
Disables the buffering of the output stream. In normal work situations, curl
uses a standard buffered output stream that has the effect that it outputs the
data in chunks, not necessarily exactly when the data arrives. Using this
option disables that buffering.

Note that this is the negated option name documented. You can use \fI\-\-buffer\fP to
enable buffering again.

Providing --no-buffer multiple times has no extra effect.
Disable it again with \-\-buffer.

Example:
.nf
 curl --no-buffer https://example.com
.fi

See also \fI-#, \-\-progress\-bar\fP.
.IP "\-\-no\-clobber"
When used in conjunction with the \fI\-o, \-\-output\fP, \fI\-J, \-\-remote\-header\-name\fP,
\fI\-O, \-\-remote\-name\fP, or \fI\-\-remote\-name\-all\fP options, curl avoids overwriting files
that already exist. Instead, a dot and a number gets appended to the name of
the file that would be created, up to filename.100 after which it does not
create any file.

Note that this is the negated option name documented. You can thus use
\fI\-\-clobber\fP to enforce the clobbering, even if \fI\-J, \-\-remote\-header\-name\fP is
specified.

Providing --no-clobber multiple times has no extra effect.
Disable it again with \-\-clobber.

Example:
.nf
 curl --no-clobber --output local/dir/file https://example.com
.fi

Added in 7.83.0. See also \fI-o, \-\-output\fP and \fI-O, \-\-remote\-name\fP.
.IP "\-\-no\-keepalive"
Disables the use of keepalive messages on the TCP connection. curl otherwise
enables them by default.

Note that this is the negated option name documented. You can thus use
\fI\-\-keepalive\fP to enforce keepalive.

Providing --no-keepalive multiple times has no extra effect.
Disable it again with \-\-keepalive.

Example:
.nf
 curl --no-keepalive https://example.com
.fi

See also \fI\-\-keepalive\-time\fP and \fI\-\-keepalive\-cnt\fP.
.IP "\-\-no\-npn"
(HTTPS) curl never uses NPN, this option has no effect (added in 7.86.0).

Disable the NPN TLS extension. NPN is enabled by default if libcurl was built
with an SSL library that supports NPN. NPN is used by a libcurl that supports
HTTP/2 to negotiate HTTP/2 support with the server during https sessions.

Providing --no-npn multiple times has no extra effect.
Disable it again with \-\-npn.

Example:
.nf
 curl --no-npn https://example.com
.fi

\fI\-\-no\-npn\fP requires that libcurl is built to support TLS.
See also \fI\-\-no\-alpn\fP and \fI\-\-http2\fP.
.IP "\-\-no\-progress\-meter"
Option to switch off the progress meter output without muting or otherwise
affecting warning and informational messages like \fI\-s, \-\-silent\fP does.

Note that this is the negated option name documented. You can thus use
\fI\-\-progress\-meter\fP to enable the progress meter again.

Providing --no-progress-meter multiple times has no extra effect.
Disable it again with \-\-progress-meter.

Example:
.nf
 curl --no-progress-meter -o store https://example.com
.fi

Added in 7.67.0. See also \fI-v, \-\-verbose\fP and \fI-s, \-\-silent\fP.
.IP "\-\-no\-sessionid"
(TLS) Disable curl\(aqs use of SSL session\-ID caching. By default all transfers are
done using the cache. Note that while nothing should ever get hurt by
attempting to reuse SSL session\-IDs, there seem to be broken SSL
implementations in the wild that may require you to disable this in order for
you to succeed.

Note that this is the negated option name documented. You can thus use
\fI\-\-sessionid\fP to enforce session\-ID caching.

Providing --no-sessionid multiple times has no extra effect.
Disable it again with \-\-sessionid.

Example:
.nf
 curl --no-sessionid https://example.com
.fi

See also \fI-k, \-\-insecure\fP.
.IP "\-\-noproxy <no\-proxy\-list>"
Comma\-separated list of hosts for which not to use a proxy, if one is
specified. The only wildcard is a single "*" character, which matches all
hosts, and effectively disables the proxy. Each name in this list is matched
as either a domain which contains the hostname, or the hostname itself. For
example, "local.com" would match "local.com", "local.com:80", and
\&"www.local.com", but not "www.notlocal.com".

This option overrides the environment variables that disable the proxy
("no_proxy" and "NO_PROXY"). If there is an environment
variable disabling a proxy, you can set the no proxy list to "" to override
it.

IP addresses specified to this option can be provided using CIDR notation
(added in 7.86.0): an appended slash and number specifies the number of
network bits out of the address to use in the comparison. For example
\&"192.168.0.0/16" would match all addresses starting with "192.168".

If --noproxy is provided several times, the last set value is used.

Example:
.nf
 curl --noproxy "www.example" https://example.com
.fi

See also \fI-x, \-\-proxy\fP.
.IP "\-\-ntlm"
(HTTP) Use NTLM authentication. The NTLM authentication method was designed by
Microsoft and is used by IIS web servers. It is a proprietary protocol,
reverse\-engineered by clever people and implemented in curl based on their
efforts. This kind of behavior should not be endorsed, you should encourage
everyone who uses NTLM to switch to a public and documented authentication
method instead, such as Digest.

If you want to enable NTLM for your proxy authentication, then use
\fI\-\-proxy\-ntlm\fP.

Providing --ntlm multiple times has no extra effect.

Example:
.nf
 curl --ntlm -u user:password https://example.com
.fi

\fI\-\-ntlm\fP requires that libcurl is built to support TLS.
This option is mutually exclusive with \fI\-\-basic\fP, \fI\-\-negotiate\fP, \fI\-\-digest\fP and \fI\-\-anyauth\fP.
See also \fI\-\-proxy\-ntlm\fP.
.IP "\-\-ntlm\-wb"
(HTTP) Deprecated option (added in 8.8.0).

Enabled NTLM much in the style \fI\-\-ntlm\fP does, but handed over the authentication
to a separate executable that was executed when needed.

Providing --ntlm-wb multiple times has no extra effect.

Example:
.nf
 curl --ntlm-wb -u user:password https://example.com
.fi

See also \fI\-\-ntlm\fP and \fI\-\-proxy\-ntlm\fP.
.IP "\-\-oauth2\-bearer <token>"
(IMAP LDAP POP3 SMTP HTTP) Specify the Bearer Token for OAUTH 2.0 server authentication. The Bearer Token
is used in conjunction with the username which can be specified as part of the
\fI\-\-url\fP or \fI\-u, \-\-user\fP options.

The Bearer Token and username are formatted according to RFC 6750.

If --oauth2-bearer is provided several times, the last set value is used.

Example:
.nf
 curl --oauth2-bearer "mF_9.B5f-4.1JqM" https://example.com
.fi

See also \fI\-\-basic\fP, \fI\-\-ntlm\fP and \fI\-\-digest\fP.
.IP "\-o, \-\-output <file>"
Write output to the given file instead of stdout. If you are using globbing to
fetch multiple documents, you should quote the URL and you can use "#"
followed by a number in the filename. That variable is then replaced with the
current string for the URL being fetched. Like in:
.nf

curl "http://{one,two}.example.com" \-o "file_#1.txt"
.fi

or use several variables like:
.nf

curl "http://{site,host}.host[1\-5].example" \-o "#1_#2"
.fi

You may use this option as many times as the number of URLs you have. For
example, if you specify two URLs on the same command line, you can use it like
this:
.nf

curl \-o aa example.com \-o bb example.net
.fi

and the order of the \-o options and the URLs does not matter, just that the
first \-o is for the first URL and so on, so the above command line can also be
written as
.nf

curl example.com example.net \-o aa \-o bb
.fi

See also the \fI\-\-create\-dirs\fP option to create the local directories
dynamically. Specifying the output as \(aq\-\(aq (a single dash) passes the output to
stdout.

To suppress response bodies, you can redirect output to /dev/null:
.nf

curl example.com \-o /dev/null
.fi

Or for Windows:
.nf

curl example.com \-o nul
.fi

Specify the filename as single minus to force the output to stdout, to
override curl\(aqs internal binary output in terminal prevention:
.nf

curl https://example.com/jpeg \-o \-
.fi

--output is associated with a single URL. Use it once per URL when you use several URLs in a command line.

Examples:
.nf
 curl -o file https://example.com
 curl "http://{one,two}.example.com" -o "file_#1.txt"
 curl "http://{site,host}.host[1-5].example" -o "#1_#2"
 curl -o file https://example.com -o file2 https://example.net
.fi

See also \fI-O, \-\-remote\-name\fP, \fI\-\-remote\-name\-all\fP and \fI-J, \-\-remote\-header\-name\fP.
.IP "\-\-output\-dir <dir>"
Specify the directory in which files should be stored, when \fI\-O, \-\-remote\-name\fP or
\fI\-o, \-\-output\fP are used.

The given output directory is used for all URLs and output options on the
command line, up until the first \fI\-:, \-\-next\fP.

If the specified target directory does not exist, the operation fails unless
\fI\-\-create\-dirs\fP is also used.

If --output-dir is provided several times, the last set value is used.

Example:
.nf
 curl --output-dir "tmp" -O https://example.com
.fi

Added in 7.73.0. See also \fI-O, \-\-remote\-name\fP and \fI-J, \-\-remote\-header\-name\fP.
.IP "\-Z, \-\-parallel"
Makes curl perform all transfers in parallel as compared to the regular serial
manner. Parallel transfer means that curl runs up to N concurrent transfers
simultaneously and if there are more than N transfers to handle, it starts new
ones when earlier transfers finish.

With parallel transfers, the progress meter output is different than when
doing serial transfers, as it then displays the transfer status for multiple
transfers in a single line.

The maximum amount of concurrent transfers is set with \fI\-\-parallel\-max\fP and it
defaults to 50.

This option is global and does not need to be specified for each use of --next.

Providing --parallel multiple times has no extra effect.
Disable it again with \-\-no-parallel.

Example:
.nf
 curl --parallel https://example.com -o file1 https://example.com -o file2
.fi

Added in 7.66.0. See also \fI-:, \-\-next\fP, \fI-v, \-\-verbose\fP, \fI\-\-parallel\-max\fP and \fI\-\-parallel\-immediate\fP.
.IP "\-\-parallel\-immediate"
When doing parallel transfers, this option instructs curl to prefer opening up
more connections in parallel at once rather than waiting to see if new
transfers can be added as multiplexed streams on another connection.

By default, without this option set, curl prefers to wait a little and
multiplex new transfers over existing connections. It keeps the number of
connections low at the expense of risking a slightly slower transfer startup.

This option is global and does not need to be specified for each use of --next.

Providing --parallel-immediate multiple times has no extra effect.
Disable it again with \-\-no-parallel-immediate.

Example:
.nf
 curl --parallel-immediate -Z https://example.com -o file1 https://example.com -o file2
.fi

Added in 7.68.0. See also \fI-Z, \-\-parallel\fP and \fI\-\-parallel\-max\fP.
.IP "\-\-parallel\-max <num>"
When asked to do parallel transfers, using \fI\-Z, \-\-parallel\fP, this option controls
the maximum amount of transfers to do simultaneously.

The default is 50. 300 is the largest supported value.

This option is global and does not need to be specified for each use of --next.

If --parallel-max is provided several times, the last set value is used.

Example:
.nf
 curl --parallel-max 100 -Z https://example.com ftp://example.com/
.fi

Added in 7.66.0. See also \fI-Z, \-\-parallel\fP.
.IP "\-\-pass <phrase>"
(SSH TLS) Passphrase for the private key.

If --pass is provided several times, the last set value is used.

Example:
.nf
 curl --pass secret --key file https://example.com
.fi

See also \fI\-\-key\fP and \fI-u, \-\-user\fP.
.IP "\-\-path\-as\-is"
Do not handle sequences of /../ or /./ in the given URL path. Normally curl
squashes or merges them according to standards but with this option set you
tell it not to do that.

Providing --path-as-is multiple times has no extra effect.
Disable it again with \-\-no-path-as-is.

Example:
.nf
 curl --path-as-is https://example.com/../../etc/passwd
.fi

See also \fI\-\-request\-target\fP.
.IP "\-\-pinnedpubkey <hashes>"
(TLS) Use the specified public key file (or hashes) to verify the peer. This can be
a path to a file which contains a single public key in PEM or DER format, or
any number of base64 encoded sha256 hashes preceded by \(aqsha256//\(aq and
separated by \(aq;\(aq.

When negotiating a TLS or SSL connection, the server sends a certificate
indicating its identity. A public key is extracted from this certificate and
if it does not exactly match the public key provided to this option, curl
aborts the connection before sending or receiving any data.

This option is independent of option \fI\-k, \-\-insecure\fP. If you use both options
together then the peer is still verified by public key.

PEM/DER support:

OpenSSL and GnuTLS, wolfSSL, mbedTLS
, Secure Transport macOS 10.7+/iOS 10+,
Schannel

sha256 support:

OpenSSL, GnuTLS and wolfSSL, mbedTLS,
Secure Transport macOS 10.7+/iOS 10+, Schannel


Other SSL backends not supported.

If --pinnedpubkey is provided several times, the last set value is used.

Examples:
.nf
 curl --pinnedpubkey keyfile https://example.com
 curl --pinnedpubkey 'sha256//ce118b51897f4452dc' https://example.com
.fi

See also \fI\-\-hostpubsha256\fP.
.IP "\-\-post301"
(HTTP) Respect RFC 7231/6.4.2 and do not convert POST requests into GET requests when
following a 301 redirect. The non\-RFC behavior is ubiquitous in web browsers,
so curl does the conversion by default to maintain consistency. However, a
server may require a POST to remain a POST after such a redirection. This
option is meaningful only when using \fI\-L, \-\-location\fP.

Providing --post301 multiple times has no extra effect.
Disable it again with \-\-no-post301.

Example:
.nf
 curl --post301 --location -d "data" https://example.com
.fi

See also \fI\-\-post302\fP, \fI\-\-post303\fP and \fI-L, \-\-location\fP.
.IP "\-\-post302"
(HTTP) Respect RFC 7231/6.4.3 and do not convert POST requests into GET requests when
following a 302 redirect. The non\-RFC behavior is ubiquitous in web browsers,
so curl does the conversion by default to maintain consistency. However, a
server may require a POST to remain a POST after such a redirection. This
option is meaningful only when using \fI\-L, \-\-location\fP.

Providing --post302 multiple times has no extra effect.
Disable it again with \-\-no-post302.

Example:
.nf
 curl --post302 --location -d "data" https://example.com
.fi

See also \fI\-\-post301\fP, \fI\-\-post303\fP and \fI-L, \-\-location\fP.
.IP "\-\-post303"
(HTTP) Violate RFC 7231/6.4.4 and do not convert POST requests into GET requests when
following 303 redirect. A server may require a POST to remain a POST after a
303 redirection. This option is meaningful only when using \fI\-L, \-\-location\fP.

Providing --post303 multiple times has no extra effect.
Disable it again with \-\-no-post303.

Example:
.nf
 curl --post303 --location -d "data" https://example.com
.fi

See also \fI\-\-post302\fP, \fI\-\-post301\fP and \fI-L, \-\-location\fP.
.IP "\-\-preproxy [protocol://]host[:port]"
Use the specified SOCKS proxy before connecting to an HTTP or HTTPS \fI\-x, \-\-proxy\fP. In
such a case curl first connects to the SOCKS proxy and then connects (through
SOCKS) to the HTTP or HTTPS proxy. Hence pre proxy.

The pre proxy string should be specified with a protocol:// prefix to specify
alternative proxy protocols. Use socks4://, socks4a://, socks5:// or
socks5h:// to request the specific SOCKS version to be used. No protocol
specified makes curl default to SOCKS4.

If the port number is not specified in the proxy string, it is assumed to be
1080.

User and password that might be provided in the proxy string are URL decoded
by curl. This allows you to pass in special characters such as @ by using %40
or pass in a colon with %3a.

If --preproxy is provided several times, the last set value is used.

Example:
.nf
 curl --preproxy socks5://proxy.example -x http://http.example https://example.com
.fi

See also \fI-x, \-\-proxy\fP and \fI\-\-socks5\fP.
.IP "\-#, \-\-progress\-bar"
Make curl display transfer progress as a simple progress bar instead of the
standard, more informational, meter.

This progress bar draws a single line of \(aq#\(aq characters across the screen and
shows a percentage if the transfer size is known. For transfers without a
known size, there is a space ship (\-=o=\-) that moves back and forth but only
while data is being transferred, with a set of flying hash sign symbols on
top.

This option is global and does not need to be specified for each use of --next.

Providing --progress-bar multiple times has no extra effect.
Disable it again with \-\-no-progress-bar.

Example:
.nf
 curl -# -O https://example.com
.fi

See also \fI\-\-styled\-output\fP.
.IP "\-\-proto <protocols>"
Limit what protocols to allow for transfers. Protocols are evaluated left to
right, are comma separated, and are each a protocol name or \(aqall\(aq, optionally
prefixed by zero or more modifiers. Available modifiers are:
.RS
.IP +
Permit this protocol in addition to protocols already permitted (this is
the default if no modifier is used).
.IP -
Deny this protocol, removing it from the list of protocols already permitted.
.IP =
Permit only this protocol (ignoring the list already permitted), though
subject to later modification by subsequent entries in the comma separated
list.
.RE
.IP
For example: \fI\-\-proto\fP \-ftps uses the default protocols, but disables ftps

\fI\-\-proto\fP \-all,https,+http only enables http and https

\fI\-\-proto\fP =http,https also only enables http and https

Unknown and disabled protocols produce a warning. This allows scripts to
safely rely on being able to disable potentially dangerous protocols, without
relying upon support for that protocol being built into curl to avoid an error.

This option can be used multiple times, in which case the effect is the same
as concatenating the protocols into one instance of the option.

If --proto is provided several times, the last set value is used.

Example:
.nf
 curl --proto =http,https,sftp https://example.com
.fi

See also \fI\-\-proto\-redir\fP and \fI\-\-proto\-default\fP.
.IP "\-\-proto\-default <protocol>"
Use \fIprotocol\fP for any provided URL missing a scheme.

An unknown or unsupported protocol causes error \fICURLE_UNSUPPORTED_PROTOCOL\fP.

This option does not change the default proxy protocol (http).

Without this option set, curl guesses protocol based on the hostname, see
\fI\-\-url\fP for details.

If --proto-default is provided several times, the last set value is used.

Example:
.nf
 curl --proto-default https ftp.example.com
.fi

See also \fI\-\-proto\fP and \fI\-\-proto\-redir\fP.
.IP "\-\-proto\-redir <protocols>"
Limit what protocols to allow on redirects. Protocols denied by \fI\-\-proto\fP are
not overridden by this option. See \fI\-\-proto\fP for how protocols are represented.

Example, allow only HTTP and HTTPS on redirect:
.nf

curl \--proto\-redir \-all,http,https http://example.com
.fi

By default curl only allows HTTP, HTTPS, FTP and FTPS on redirects
(added in 7.65.2). Specifying \fIall\fP or \fI+all\fP enables all protocols on
redirects, which is not good for security.

If --proto-redir is provided several times, the last set value is used.

Example:
.nf
 curl --proto-redir =http,https https://example.com
.fi

See also \fI\-\-proto\fP.
.IP "\-x, \-\-proxy [protocol://]host[:port]"
Use the specified proxy.

The proxy string can be specified with a protocol:// prefix. No protocol
specified or http:// it is treated as an HTTP proxy. Use socks4://,
socks4a://, socks5:// or socks5h:// to request a specific SOCKS version to be
used.

Unix domain sockets are supported for socks proxy. Set localhost for the host
part. e.g. socks5h://localhost/path/to/socket.sock

HTTPS proxy support works set with the https:// protocol prefix for OpenSSL
and GnuTLS. It also works for BearSSL, mbedTLS, rustls,
Schannel, Secure Transport and wolfSSL (added in 7.87.0).

Unrecognized and unsupported proxy protocols cause an error.
Ancient curl versions ignored unknown schemes and used http:// instead.

If the port number is not specified in the proxy string, it is assumed to be
1080.

This option overrides existing environment variables that set the proxy to
use. If there is an environment variable setting a proxy, you can set proxy to
\&"" to override it.

All operations that are performed over an HTTP proxy are transparently
converted to HTTP. It means that certain protocol specific operations might
not be available. This is not the case if you can tunnel through the proxy, as
one with the \fI\-p, \-\-proxytunnel\fP option.

User and password that might be provided in the proxy string are URL decoded
by curl. This allows you to pass in special characters such as @ by using %40
or pass in a colon with %3a.

The proxy host can be specified the same way as the proxy environment
variables, including the protocol prefix (http://) and the embedded user +
password.

When a proxy is used, the active FTP mode as set with \fI\-P, \-\-ftp\-port\fP, cannot be
used.

If --proxy is provided several times, the last set value is used.

Example:
.nf
 curl --proxy http://proxy.example https://example.com
.fi

See also \fI\-\-socks5\fP and \fI\-\-proxy\-basic\fP.
.IP "\-\-proxy\-anyauth"
Automatically pick a suitable authentication method when communicating with
the given HTTP proxy. This might cause an extra request/response round\-trip.

Providing --proxy-anyauth multiple times has no extra effect.

Example:
.nf
 curl --proxy-anyauth --proxy-user user:passwd -x proxy https://example.com
.fi

See also \fI-x, \-\-proxy\fP, \fI\-\-proxy\-basic\fP and \fI\-\-proxy\-digest\fP.
.IP "\-\-proxy\-basic"
Use HTTP Basic authentication when communicating with the given proxy. Use
\fI\-\-basic\fP for enabling HTTP Basic with a remote host. Basic is the default
authentication method curl uses with proxies.

Providing --proxy-basic multiple times has no extra effect.

Example:
.nf
 curl --proxy-basic --proxy-user user:passwd -x proxy https://example.com
.fi

See also \fI-x, \-\-proxy\fP, \fI\-\-proxy\-anyauth\fP and \fI\-\-proxy\-digest\fP.
.IP "\-\-proxy\-ca\-native"
(TLS) Use the CA store from the native operating system to verify the HTTPS proxy.
By default, curl uses a CA store provided in a single file or directory, but
when using this option it interfaces the operating system\(aqs own vault.

This option works for curl on Windows when built to use OpenSSL, wolfSSL
(added in 8.3.0) or GnuTLS (added in 8.5.0). When curl on Windows is built to
use Schannel, this feature is implied and curl then only uses the native CA
store.

Providing --proxy-ca-native multiple times has no extra effect.
Disable it again with \-\-no-proxy-ca-native.

Example:
.nf
 curl --proxy-ca-native https://example.com
.fi

Added in 8.2.0. See also \fI\-\-cacert\fP, \fI\-\-capath\fP and \fI-k, \-\-insecure\fP.
.IP "\-\-proxy\-cacert <file>"
Use the specified certificate file to verify the HTTPS proxy. The file may
contain multiple CA certificates. The certificate(s) must be in PEM format.

This allows you to use a different trust for the proxy compared to the remote
server connected to via the proxy.

Equivalent to \fI\-\-cacert\fP but used in HTTPS proxy context.

If --proxy-cacert is provided several times, the last set value is used.

Example:
.nf
 curl --proxy-cacert CA-file.txt -x https://proxy https://example.com
.fi

See also \fI\-\-proxy\-capath\fP, \fI\-\-cacert\fP, \fI\-\-capath\fP and \fI-x, \-\-proxy\fP.
.IP "\-\-proxy\-capath <dir>"
Same as \fI\-\-capath\fP but used in HTTPS proxy context.

Use the specified certificate directory to verify the proxy. Multiple paths
can be provided by separated with colon (":") (e.g. "path1:path2:path3"). The
certificates must be in PEM format, and if curl is built against OpenSSL, the
directory must have been processed using the c_rehash utility supplied with
OpenSSL. Using \fI\-\-proxy\-capath\fP can allow OpenSSL\-powered curl to make
SSL\-connections much more efficiently than using \fI\-\-proxy\-cacert\fP if the
\fI\-\-proxy\-cacert\fP file contains many CA certificates.

If this option is set, the default capath value is ignored.

If --proxy-capath is provided several times, the last set value is used.

Example:
.nf
 curl --proxy-capath /local/directory -x https://proxy https://example.com
.fi

See also \fI\-\-proxy\-cacert\fP, \fI-x, \-\-proxy\fP and \fI\-\-capath\fP.
.IP "\-\-proxy\-cert <cert[:passwd]>"
Use the specified client certificate file when communicating with an HTTPS
proxy. The certificate must be in PKCS#12 format if using Secure Transport, or
PEM format if using any other engine. If the optional password is not
specified, it is queried for on the terminal. Use \fI\-\-proxy\-key\fP to provide the
private key.

This option is the equivalent to \fI\-E, \-\-cert\fP but used in HTTPS proxy context.

If --proxy-cert is provided several times, the last set value is used.

Example:
.nf
 curl --proxy-cert file -x https://proxy https://example.com
.fi

See also \fI-x, \-\-proxy\fP, \fI\-\-proxy\-key\fP and \fI\-\-proxy\-cert\-type\fP.
.IP "\-\-proxy\-cert\-type <type>"
Set type of the provided client certificate when using HTTPS proxy. PEM, DER,
ENG and P12 are recognized types.

The default type depends on the TLS backend and is usually PEM, however for
Secure Transport and Schannel it is P12. If \fI\-\-proxy\-cert\fP is a pkcs11: URI then
ENG is the default type.

Equivalent to \fI\-\-cert\-type\fP but used in HTTPS proxy context.

If --proxy-cert-type is provided several times, the last set value is used.

Example:
.nf
 curl --proxy-cert-type PEM --proxy-cert file -x https://proxy https://example.com
.fi

See also \fI\-\-proxy\-cert\fP and \fI\-\-proxy\-key\fP.
.IP "\-\-proxy\-ciphers <list>"
Same as \fI\-\-ciphers\fP but used in HTTPS proxy context.

Specifies which ciphers to use in the connection to the HTTPS proxy. The list
of ciphers must specify valid ciphers. Read up on SSL cipher list details on
this URL:

https://curl.se/docs/ssl\-ciphers.html

If --proxy-ciphers is provided several times, the last set value is used.

Example:
.nf
 curl --proxy-ciphers ECDHE-ECDSA-AES256-CCM8 -x https://proxy https://example.com
.fi

See also \fI\-\-ciphers\fP, \fI\-\-curves\fP and \fI-x, \-\-proxy\fP.
.IP "\-\-proxy\-crlfile <file>"
Provide filename for a PEM formatted file with a Certificate Revocation List
that specifies peer certificates that are considered revoked when
communicating with an HTTPS proxy.

Equivalent to \fI\-\-crlfile\fP but only used in HTTPS proxy context.

If --proxy-crlfile is provided several times, the last set value is used.

Example:
.nf
 curl --proxy-crlfile rejects.txt -x https://proxy https://example.com
.fi

See also \fI\-\-crlfile\fP and \fI-x, \-\-proxy\fP.
.IP "\-\-proxy\-digest"
Use HTTP Digest authentication when communicating with the given proxy. Use
\fI\-\-digest\fP for enabling HTTP Digest with a remote host.

Providing --proxy-digest multiple times has no extra effect.

Example:
.nf
 curl --proxy-digest --proxy-user user:passwd -x proxy https://example.com
.fi

See also \fI-x, \-\-proxy\fP, \fI\-\-proxy\-anyauth\fP and \fI\-\-proxy\-basic\fP.
.IP "\-\-proxy\-header <header/@file>"
(HTTP) Extra header to include in the request when sending HTTP to a proxy. You may
specify any number of extra headers. This is the equivalent option to \fI\-H, \-\-header\fP
but is for proxy communication only like in CONNECT requests when you want a
separate header sent to the proxy to what is sent to the actual remote host.

curl makes sure that each header you add/replace is sent with the proper
end\-of\-line marker, you should thus \fBnot\fP add that as a part of the header
content: do not add newlines or carriage returns, they only mess things up for
you.

Headers specified with this option are not included in requests that curl
knows are not be sent to a proxy.

This option can take an argument in @filename style, which then adds a header
for each line in the input file. Using @\- makes curl read
the headers from stdin.

This option can be used multiple times to add/replace/remove multiple headers.

--proxy-header can be used several times in a command line

Examples:
.nf
 curl --proxy-header "X-First-Name: Joe" -x http://proxy https://example.com
 curl --proxy-header "User-Agent: surprise" -x http://proxy https://example.com
 curl --proxy-header "Host:" -x http://proxy https://example.com
.fi

See also \fI-x, \-\-proxy\fP.
.IP "\-\-proxy\-http2"
(HTTP) Negotiate HTTP/2 with an HTTPS proxy. The proxy might still only offer HTTP/1
and then curl sticks to using that version.

This has no effect for any other kinds of proxies.

Providing --proxy-http2 multiple times has no extra effect.
Disable it again with \-\-no-proxy-http2.

Example:
.nf
 curl --proxy-http2 -x proxy https://example.com
.fi

\fI\-\-proxy\-http2\fP requires that libcurl is built to support HTTP/2.
Added in 8.1.0. See also \fI-x, \-\-proxy\fP.
.IP "\-\-proxy\-insecure"
Same as \fI\-k, \-\-insecure\fP but used in HTTPS proxy context.

Every secure connection curl makes is verified to be secure before the
transfer takes place. This option makes curl skip the verification step with a
proxy and proceed without checking.

When this option is not used for a proxy using HTTPS, curl verifies the
proxy\(aqs TLS certificate before it continues: that the certificate contains the
right name which matches the hostname and that the certificate has been signed
by a CA certificate present in the cert store. See this online resource for
further details: \fBhttps://curl.se/docs/sslcerts.html\fP

\fBWARNING\fP: using this option makes the transfer to the proxy insecure.

Providing --proxy-insecure multiple times has no extra effect.
Disable it again with \-\-no-proxy-insecure.

Example:
.nf
 curl --proxy-insecure -x https://proxy https://example.com
.fi

See also \fI-x, \-\-proxy\fP and \fI-k, \-\-insecure\fP.
.IP "\-\-proxy\-key <key>"
Specify the filename for your private key when using client certificates with
your HTTPS proxy. This option is the equivalent to \fI\-\-key\fP but used in HTTPS
proxy context.

If --proxy-key is provided several times, the last set value is used.

Example:
.nf
 curl --proxy-key here -x https://proxy https://example.com
.fi

See also \fI\-\-proxy\-key\-type\fP and \fI-x, \-\-proxy\fP.
.IP "\-\-proxy\-key\-type <type>"
Specify the private key file type your \fI\-\-proxy\-key\fP provided private key uses.
DER, PEM, and ENG are supported. If not specified, PEM is assumed.

Equivalent to \fI\-\-key\-type\fP but used in HTTPS proxy context.

If --proxy-key-type is provided several times, the last set value is used.

Example:
.nf
 curl --proxy-key-type DER --proxy-key here -x https://proxy https://example.com
.fi

See also \fI\-\-proxy\-key\fP and \fI-x, \-\-proxy\fP.
.IP "\-\-proxy\-negotiate"
Use HTTP Negotiate (SPNEGO) authentication when communicating with the given
proxy. Use \fI\-\-negotiate\fP for enabling HTTP Negotiate (SPNEGO) with a remote
host.

Providing --proxy-negotiate multiple times has no extra effect.

Example:
.nf
 curl --proxy-negotiate --proxy-user user:passwd -x proxy https://example.com
.fi

See also \fI\-\-proxy\-anyauth\fP, \fI\-\-proxy\-basic\fP and \fI\-\-proxy\-service\-name\fP.
.IP "\-\-proxy\-ntlm"
Use HTTP NTLM authentication when communicating with the given proxy. Use
\fI\-\-ntlm\fP for enabling NTLM with a remote host.

Providing --proxy-ntlm multiple times has no extra effect.

Example:
.nf
 curl --proxy-ntlm --proxy-user user:passwd -x http://proxy https://example.com
.fi

See also \fI\-\-proxy\-negotiate\fP, \fI\-\-proxy\-anyauth\fP and \fI-U, \-\-proxy\-user\fP.
.IP "\-\-proxy\-pass <phrase>"
Passphrase for the private key for HTTPS proxy client certificate.

Equivalent to \fI\-\-pass\fP but used in HTTPS proxy context.

If --proxy-pass is provided several times, the last set value is used.

Example:
.nf
 curl --proxy-pass secret --proxy-key here -x https://proxy https://example.com
.fi

See also \fI-x, \-\-proxy\fP and \fI\-\-proxy\-key\fP.
.IP "\-\-proxy\-pinnedpubkey <hashes>"
(TLS) Use the specified public key file (or hashes) to verify the proxy. This can be
a path to a file which contains a single public key in PEM or DER format, or
any number of base64 encoded sha256 hashes preceded by \(aqsha256//\(aq and
separated by \(aq;\(aq.

When negotiating a TLS or SSL connection, the server sends a certificate
indicating its identity. A public key is extracted from this certificate and
if it does not exactly match the public key provided to this option, curl
aborts the connection before sending or receiving any data.

If --proxy-pinnedpubkey is provided several times, the last set value is used.

Examples:
.nf
 curl --proxy-pinnedpubkey keyfile https://example.com
 curl --proxy-pinnedpubkey 'sha256//ce118b51897f4452dc' https://example.com
.fi

See also \fI\-\-pinnedpubkey\fP and \fI-x, \-\-proxy\fP.
.IP "\-\-proxy\-service\-name <name>"
Set the service name for SPNEGO when doing proxy authentication.

If --proxy-service-name is provided several times, the last set value is used.

Example:
.nf
 curl --proxy-service-name "shrubbery" -x proxy https://example.com
.fi

See also \fI\-\-service\-name\fP, \fI-x, \-\-proxy\fP and \fI\-\-proxy\-negotiate\fP.
.IP "\-\-proxy\-ssl\-allow\-beast"
Do not work around a security flaw in the TLS1.0 protocol known as BEAST when
communicating to an HTTPS proxy. If this option is not used, the TLS layer may
use workarounds known to cause interoperability problems with some older
server implementations.

This option only changes how curl does TLS 1.0 with an HTTPS proxy and has no
effect on later TLS versions.

\fBWARNING\fP: this option loosens the TLS security, and by using this flag you
ask for exactly that.

Equivalent to \fI\-\-ssl\-allow\-beast\fP but used in HTTPS proxy context.

Providing --proxy-ssl-allow-beast multiple times has no extra effect.
Disable it again with \-\-no-proxy-ssl-allow-beast.

Example:
.nf
 curl --proxy-ssl-allow-beast -x https://proxy https://example.com
.fi

See also \fI\-\-ssl\-allow\-beast\fP and \fI-x, \-\-proxy\fP.
.IP "\-\-proxy\-ssl\-auto\-client\-cert"
Same as \fI\-\-ssl\-auto\-client\-cert\fP but used in HTTPS proxy context.

This is only supported by Schannel.

Providing --proxy-ssl-auto-client-cert multiple times has no extra effect.
Disable it again with \-\-no-proxy-ssl-auto-client-cert.

Example:
.nf
 curl --proxy-ssl-auto-client-cert -x https://proxy https://example.com
.fi

Added in 7.77.0. See also \fI\-\-ssl\-auto\-client\-cert\fP and \fI-x, \-\-proxy\fP.
.IP "\-\-proxy\-tls13\-ciphers <ciphersuite list>"
(TLS) Specify which cipher suites to use in the connection to your HTTPS proxy when
it negotiates TLS 1.3. The list of ciphers suites must specify valid ciphers.
Read up on TLS 1.3 cipher suite details on this URL:

https://curl.se/docs/ssl\-ciphers.html

This option is currently used only when curl is built to use OpenSSL 1.1.1 or
later. If you are using a different SSL backend you can try setting TLS 1.3
cipher suites by using the \fI\-\-proxy\-ciphers\fP option.

If --proxy-tls13-ciphers is provided several times, the last set value is used.

Example:
.nf
 curl --proxy-tls13-ciphers TLS_AES_128_GCM_SHA256 -x proxy https://example.com
.fi

Added in 7.61.0. See also \fI\-\-tls13\-ciphers\fP, \fI\-\-curves\fP and \fI\-\-proxy\-ciphers\fP.
.IP "\-\-proxy\-tlsauthtype <type>"
Set TLS authentication type with HTTPS proxy. The only supported option is
\&"SRP", for TLS\-SRP (RFC 5054). This option works only if the underlying
libcurl is built with TLS\-SRP support.

Equivalent to \fI\-\-tlsauthtype\fP but used in HTTPS proxy context.

If --proxy-tlsauthtype is provided several times, the last set value is used.

Example:
.nf
 curl --proxy-tlsauthtype SRP -x https://proxy https://example.com
.fi

See also \fI-x, \-\-proxy\fP, \fI\-\-proxy\-tlsuser\fP and \fI\-\-proxy\-tlspassword\fP.
.IP "\-\-proxy\-tlspassword <string>"
Set password to use with the TLS authentication method specified with
\fI\-\-proxy\-tlsauthtype\fP when using HTTPS proxy. Requires that \fI\-\-proxy\-tlsuser\fP is
set.

This option does not work with TLS 1.3.

Equivalent to \fI\-\-tlspassword\fP but used in HTTPS proxy context.

If --proxy-tlspassword is provided several times, the last set value is used.

Example:
.nf
 curl --proxy-tlspassword passwd -x https://proxy https://example.com
.fi

See also \fI-x, \-\-proxy\fP and \fI\-\-proxy\-tlsuser\fP.
.IP "\-\-proxy\-tlsuser <name>"
Set username for use for HTTPS proxy with the TLS authentication method
specified with \fI\-\-proxy\-tlsauthtype\fP. Requires that \fI\-\-proxy\-tlspassword\fP also is
set.

This option does not work with TLS 1.3.

If --proxy-tlsuser is provided several times, the last set value is used.

Example:
.nf
 curl --proxy-tlsuser smith -x https://proxy https://example.com
.fi

See also \fI-x, \-\-proxy\fP and \fI\-\-proxy\-tlspassword\fP.
.IP "\-\-proxy\-tlsv1"
Use at least TLS version 1.x when negotiating with an HTTPS proxy. That means
TLS version 1.0 or higher

Equivalent to \fI\-1, \-\-tlsv1\fP but for an HTTPS proxy context.

Providing --proxy-tlsv1 multiple times has no extra effect.

Example:
.nf
 curl --proxy-tlsv1 -x https://proxy https://example.com
.fi

See also \fI-x, \-\-proxy\fP.
.IP "\-U, \-\-proxy\-user <user:password>"
Specify the username and password to use for proxy authentication.

If you use a Windows SSPI\-enabled curl binary and do either Negotiate or NTLM
authentication then you can tell curl to select the username and password from
your environment by specifying a single colon with this option: "\-U :".

On systems where it works, curl hides the given option argument from process
listings. This is not enough to protect credentials from possibly getting seen
by other users on the same system as they still are visible for a moment
before cleared. Such sensitive data should be retrieved from a file instead or
similar and never used in clear text in a command line.

If --proxy-user is provided several times, the last set value is used.

Example:
.nf
 curl --proxy-user smith:secret -x proxy https://example.com
.fi

See also \fI\-\-proxy\-pass\fP.
.IP "\-\-proxy1.0 <host[:port]>"
Use the specified HTTP 1.0 proxy. If the port number is not specified, it is
assumed at port 1080.

The only difference between this and the HTTP proxy option \fI\-x, \-\-proxy\fP, is that
attempts to use CONNECT through the proxy specifies an HTTP 1.0 protocol
instead of the default HTTP 1.1.

Providing --proxy1.0 multiple times has no extra effect.

Example:
.nf
 curl --proxy1.0 http://proxy https://example.com
.fi

See also \fI-x, \-\-proxy\fP, \fI\-\-socks5\fP and \fI\-\-preproxy\fP.
.IP "\-p, \-\-proxytunnel"
When an HTTP proxy is used \fI\-x, \-\-proxy\fP, this option makes curl tunnel the traffic
through the proxy. The tunnel approach is made with the HTTP proxy CONNECT
request and requires that the proxy allows direct connect to the remote port
number curl wants to tunnel through to.

To suppress proxy CONNECT response headers when curl is set to output headers
use \fI\-\-suppress\-connect\-headers\fP.

Providing --proxytunnel multiple times has no extra effect.
Disable it again with \-\-no-proxytunnel.

Example:
.nf
 curl --proxytunnel -x http://proxy https://example.com
.fi

See also \fI-x, \-\-proxy\fP.
.IP "\-\-pubkey <key>"
(SFTP SCP) Public key filename. Allows you to provide your public key in this separate
file.

curl attempts to automatically extract the public key from the private key
file, so passing this option is generally not required. Note that this public
key extraction requires libcurl to be linked against a copy of libssh2 1.2.8
or higher that is itself linked against OpenSSL.

If --pubkey is provided several times, the last set value is used.

Example:
.nf
 curl --pubkey file.pub sftp://example.com/
.fi

See also \fI\-\-pass\fP.
.IP "\-Q, \-\-quote <command>"
(FTP SFTP) Send an arbitrary command to the remote FTP or SFTP server. Quote commands are
sent BEFORE the transfer takes place (just after the initial \fBPWD\fP command
in an FTP transfer, to be exact). To make commands take place after a
successful transfer, prefix them with a dash \(aq\-\(aq.

(FTP only) To make commands be sent after curl has changed the working
directory, just before the file transfer command(s), prefix the command with a
\(aq+\(aq. This is not performed when a directory listing is performed.

You may specify any number of commands.

By default curl stops at first failure. To make curl continue even if the
command fails, prefix the command with an asterisk (*). Otherwise, if the
server returns failure for one of the commands, the entire operation is
aborted.

You must send syntactically correct FTP commands as RFC 959 defines to FTP
servers, or one of the commands listed below to SFTP servers.

SFTP is a binary protocol. Unlike for FTP, curl interprets SFTP quote commands
itself before sending them to the server. Filenames may be quoted shell\-style
to embed spaces or special characters. Following is the list of all supported
SFTP quote commands:
.RS
.IP "atime date file"
The atime command sets the last access time of the file named by the file
operand. The date expression can be all sorts of date strings, see the
\fIcurl_getdate(3)\fP man page for date expression details. (Added in 7.73.0)
.IP "chgrp group file"
The chgrp command sets the group ID of the file named by the file operand to
the group ID specified by the group operand. The group operand is a decimal
integer group ID.
.IP "chmod mode file"
The chmod command modifies the file mode bits of the specified file. The
mode operand is an octal integer mode number.
.IP "chown user file"
The chown command sets the owner of the file named by the file operand to the
user ID specified by the user operand. The user operand is a decimal
integer user ID.
.IP "ln source_file target_file"
The ln and symlink commands create a symbolic link at the target_file location
pointing to the source_file location.
.IP "mkdir directory_name"
The mkdir command creates the directory named by the directory_name operand.
.IP "mtime date file"
The mtime command sets the last modification time of the file named by the
file operand. The date expression can be all sorts of date strings, see the
\fIcurl_getdate(3)\fP man page for date expression details. (Added in 7.73.0)
.IP pwd
The pwd command returns the absolute path name of the current working directory.
.IP "rename source target"
The rename command renames the file or directory named by the source
operand to the destination path named by the target operand.
.IP "rm file"
The rm command removes the file specified by the file operand.
.IP "rmdir directory"
The rmdir command removes the directory entry specified by the directory
operand, provided it is empty.
.IP "symlink source_file target_file"
See ln.
.RE
.IP

--quote can be used several times in a command line

Example:
.nf
 curl --quote "DELE file" ftp://example.com/foo
.fi

See also \fI-X, \-\-request\fP.
.IP "\-\-random\-file <file>"
Deprecated option. This option is ignored (added in 7.84.0). Prior to that it
only had an effect on curl if built to use old versions of OpenSSL.

Specify the path name to file containing random data. The data may be used to
seed the random engine for SSL connections.

If --random-file is provided several times, the last set value is used.

Example:
.nf
 curl --random-file rubbish https://example.com
.fi

See also \fI\-\-egd\-file\fP.
.IP "\-r, \-\-range <range>"
(HTTP FTP SFTP FILE) Retrieve a byte range (i.e. a partial document) from an HTTP/1.1, FTP or SFTP
server or a local FILE. Ranges can be specified in a number of ways.
.RS
.IP 0-499
specifies the first 500 bytes
.IP 500-999
specifies the second 500 bytes
.IP -500
specifies the last 500 bytes
.IP 9500-
specifies the bytes from offset 9500 and forward
.IP 0-0,-1
specifies the first and last byte only(*)(HTTP)
.IP 100-199,500-599
specifies two separate 100\-byte ranges(*) (HTTP)
.RE
.IP
(*) = NOTE that these make the server reply with a multipart response, which
is returned as\-is by curl! Parsing or otherwise transforming this response is
the responsibility of the caller.

Only digit characters (0\-9) are valid in the \(aqstart\(aq and \(aqstop\(aq fields of the
\(aqstart\-stop\(aq range syntax. If a non\-digit character is given in the range, the
server\(aqs response is unspecified, depending on the server\(aqs configuration.

Many HTTP/1.1 servers do not have this feature enabled, so that when you
attempt to get a range, curl instead gets the whole document.

FTP and SFTP range downloads only support the simple \(aqstart\-stop\(aq syntax
(optionally with one of the numbers omitted). FTP use depends on the extended
FTP command SIZE.

If --range is provided several times, the last set value is used.

Example:
.nf
 curl --range 22-44 https://example.com
.fi

See also \fI-C, \-\-continue\-at\fP and \fI-a, \-\-append\fP.
.IP "\-\-rate <max request rate>"
Specify the maximum transfer frequency you allow curl to use \- in number of
transfer starts per time unit (sometimes called request rate). Without this
option, curl starts the next transfer as fast as possible.

If given several URLs and a transfer completes faster than the allowed rate,
curl waits until the next transfer is started to maintain the requested
rate. This option has no effect when \fI\-Z, \-\-parallel\fP is used.

The request rate is provided as "N/U" where N is an integer number and U is a
time unit. Supported units are \(aqs\(aq (second), \(aqm\(aq (minute), \(aqh\(aq (hour) and \(aqd\(aq
/(day, as in a 24 hour unit). The default time unit, if no "/U" is provided,
is number of transfers per hour.

If curl is told to allow 10 requests per minute, it does not start the next
request until 6 seconds have elapsed since the previous transfer was started.

This function uses millisecond resolution. If the allowed frequency is set
more than 1000 per second, it instead runs unrestricted.

When retrying transfers, enabled with \fI\-\-retry\fP, the separate retry delay logic
is used and not this setting.

This option is global and does not need to be specified for each use of --next.

If --rate is provided several times, the last set value is used.

Examples:
.nf
 curl --rate 2/s https://example.com ...
 curl --rate 3/h https://example.com ...
 curl --rate 14/m https://example.com ...
.fi

Added in 7.84.0. See also \fI\-\-limit\-rate\fP and \fI\-\-retry\-delay\fP.
.IP "\-\-raw"
(HTTP) When used, it disables all internal HTTP decoding of content or transfer
encodings and instead makes them passed on unaltered, raw.

Providing --raw multiple times has no extra effect.
Disable it again with \-\-no-raw.

Example:
.nf
 curl --raw https://example.com
.fi

See also \fI\-\-tr\-encoding\fP.
.IP "\-e, \-\-referer <URL>"
(HTTP) Set the referrer URL in the HTTP request. This can also be set with the
\fI\-H, \-\-header\fP flag of course. When used with \fI\-L, \-\-location\fP you can append ";auto"" to
the \fI\-e, \-\-referer\fP URL to make curl automatically set the previous URL when it
follows a Location: header. The ";auto" string can be used alone, even if you
do not set an initial \fI\-e, \-\-referer\fP.

If --referer is provided several times, the last set value is used.

Examples:
.nf
 curl --referer "https://fake.example" https://example.com
 curl --referer "https://fake.example;auto" -L https://example.com
 curl --referer ";auto" -L https://example.com
.fi

See also \fI-A, \-\-user\-agent\fP and \fI-H, \-\-header\fP.
.IP "\-J, \-\-remote\-header\-name"
(HTTP) Tell the \fI\-O, \-\-remote\-name\fP option to use the server\-specified Content\-Disposition
filename instead of extracting a filename from the URL. If the server\-provided
filename contains a path, that is stripped off before the filename is used.

The file is saved in the current directory, or in the directory specified with
\fI\-\-output\-dir\fP.

If the server specifies a filename and a file with that name already exists in
the destination directory, it is not overwritten and an error occurs \- unless
you allow it by using the \fI\-\-clobber\fP option. If the server does not specify a
filename then this option has no effect.

There is no attempt to decode %\-sequences (yet) in the provided filename, so
this option may provide you with rather unexpected filenames.

This feature uses the name from the "filename" field, it does not yet support
the "filename*" field (filenames with explicit character sets).

\fBWARNING\fP: Exercise judicious use of this option, especially on Windows. A
rogue server could send you the name of a DLL or other file that could be
loaded automatically by Windows or some third party software.

Providing --remote-header-name multiple times has no extra effect.
Disable it again with \-\-no-remote-header-name.

Example:
.nf
 curl -OJ https://example.com/file
.fi

See also \fI-O, \-\-remote\-name\fP.
.IP "\-O, \-\-remote\-name"
Write output to a local file named like the remote file we get. (Only the file
part of the remote file is used, the path is cut off.)

The file is saved in the current working directory. If you want the file saved
in a different directory, make sure you change the current working directory
before invoking curl with this option or use \fI\-\-output\-dir\fP.

The remote filename to use for saving is extracted from the given URL, nothing
else, and if it already exists it is overwritten. If you want the server to be
able to choose the filename refer to \fI\-J, \-\-remote\-header\-name\fP which can be used in
addition to this option. If the server chooses a filename and that name
already exists it is not overwritten.

There is no URL decoding done on the filename. If it has %20 or other URL
encoded parts of the name, they end up as\-is as filename.

You may use this option as many times as the number of URLs you have.

--remote-name is associated with a single URL. Use it once per URL when you use several URLs in a command line.

Examples:
.nf
 curl -O https://example.com/filename
 curl -O https://example.com/filename -O https://example.com/file2
.fi

See also \fI\-\-remote\-name\-all\fP, \fI\-\-output\-dir\fP and \fI-J, \-\-remote\-header\-name\fP.
.IP "\-\-remote\-name\-all"
Change the default action for all given URLs to be dealt with as if
\fI\-O, \-\-remote\-name\fP were used for each one. If you want to disable that for a
specific URL after \fI\-\-remote\-name\-all\fP has been used, you must use "\-o \-" or
\fI\-\-no\-remote\-name\fP.

Providing --remote-name-all multiple times has no extra effect.
Disable it again with \-\-no-remote-name-all.

Example:
.nf
 curl --remote-name-all ftp://example.com/file1 ftp://example.com/file2
.fi

See also \fI-O, \-\-remote\-name\fP.
.IP "\-R, \-\-remote\-time"
Makes curl attempt to figure out the timestamp of the remote file that is
getting downloaded, and if that is available make the local file get that same
timestamp.

Providing --remote-time multiple times has no extra effect.
Disable it again with \-\-no-remote-time.

Example:
.nf
 curl --remote-time -o foo https://example.com
.fi

See also \fI-O, \-\-remote\-name\fP and \fI-z, \-\-time\-cond\fP.
.IP "\-\-remove\-on\-error"
Remove output file if an error occurs. If curl returns an error when told to
save output in a local file. This prevents curl from leaving a partial file in
the case of an error during transfer.

If the output is not a regular file, this option has no effect.

Providing --remove-on-error multiple times has no extra effect.
Disable it again with \-\-no-remove-on-error.

Example:
.nf
 curl --remove-on-error -o output https://example.com
.fi

Added in 7.83.0. See also \fI-f, \-\-fail\fP.
.IP "\-X, \-\-request <method>"
Change the method to use when starting the transfer.

curl passes on the verbatim string you give it in the request without any
filter or other safe guards. That includes white space and control characters.
.RS
.IP HTTP
Specifies a custom request method to use when communicating with the HTTP
server. The specified request method is used instead of the method otherwise
used (which defaults to \fIGET\fP). Read the HTTP 1.1 specification for details
and explanations. Common additional HTTP requests include \fIPUT\fP and \fIDELETE\fP,
while related technologies like WebDAV offers \fIPROPFIND\fP, \fICOPY\fP, \fIMOVE\fP and
more.

Normally you do not need this option. All sorts of \fIGET\fP, \fIHEAD\fP, \fIPOST\fP and
\fIPUT\fP requests are rather invoked by using dedicated command line options.

This option only changes the actual word used in the HTTP request, it does not
alter the way curl behaves. For example if you want to make a proper HEAD
request, using \-X HEAD does not suffice. You need to use the \fI\-I, \-\-head\fP option.

The method string you set with \fI\-X, \-\-request\fP is used for all requests, which
if you for example use \fI\-L, \-\-location\fP may cause unintended side\-effects when curl
does not change request method according to the HTTP 30x response codes \- and
similar.
.IP FTP
Specifies a custom FTP command to use instead of \fILIST\fP when doing file lists
with FTP.
.IP POP3
Specifies a custom POP3 command to use instead of \fILIST\fP or \fIRETR\fP.

.IP IMAP
Specifies a custom IMAP command to use instead of \fILIST\fP.
.IP SMTP
Specifies a custom SMTP command to use instead of \fIHELP\fP or \fBVRFY\fP.
.RE
.IP

If --request is provided several times, the last set value is used.

Examples:
.nf
 curl -X "DELETE" https://example.com
 curl -X NLST ftp://example.com/
.fi

See also \fI\-\-request\-target\fP.
.IP "\-\-request\-target <path>"
(HTTP) Use an alternative target (path) instead of using the path as provided in the
URL. Particularly useful when wanting to issue HTTP requests without leading
slash or other data that does not follow the regular URL pattern, like
\&"OPTIONS *".

curl passes on the verbatim string you give it its the request without any
filter or other safe guards. That includes white space and control characters.

If --request-target is provided several times, the last set value is used.

Example:
.nf
 curl --request-target "*" -X OPTIONS https://example.com
.fi

See also \fI-X, \-\-request\fP.
.IP "\-\-resolve <[+]host:port:addr[,addr]...>"
Provide a custom address for a specific host and port pair. Using this, you
can make the curl requests(s) use a specified address and prevent the
otherwise normally resolved address to be used. Consider it a sort of
/etc/hosts alternative provided on the command line. The port number should be
the number used for the specific protocol the host is used for. It means
you need several entries if you want to provide address for the same host but
different ports.

By specifying "*" as host you can tell curl to resolve any host and specific
port pair to the specified address. Wildcard is resolved last so any \fI\-\-resolve\fP
with a specific host and port is used first.

The provided address set by this option is used even if \fI\-4, \-\-ipv4\fP or \fI\-6, \-\-ipv6\fP is
set to make curl use another IP version.

By prefixing the host with a \(aq+\(aq you can make the entry time out after curl\(aqs
default timeout (1 minute). Note that this only makes sense for long running
parallel transfers with a lot of files. In such cases, if this option is used
curl tries to resolve the host as it normally would once the timeout has
expired.

To redirect connects from a specific hostname or any hostname, independently
of port number, consider the \fI\-\-connect\-to\fP option.

Support for resolving with wildcard was added in 7.64.0.

Support for the \(aq+\(aq prefix was added in 7.75.0.

--resolve can be used several times in a command line

Example:
.nf
 curl --resolve example.com:443:127.0.0.1 https://example.com
.fi

See also \fI\-\-connect\-to\fP and \fI\-\-alt\-svc\fP.
.IP "\-\-retry <num>"
If a transient error is returned when curl tries to perform a transfer, it
retries this number of times before giving up. Setting the number to 0
makes curl do no retries (which is the default). Transient error means either:
a timeout, an FTP 4xx response code or an HTTP 408, 429, 500, 502, 503 or 504
response code.

When curl is about to retry a transfer, it first waits one second and then for
all forthcoming retries it doubles the waiting time until it reaches 10
minutes which then remains delay between the rest of the retries. By using
\fI\-\-retry\-delay\fP you disable this exponential backoff algorithm. See also
\fI\-\-retry\-max\-time\fP to limit the total time allowed for retries.

curl complies with the Retry\-After: response header if one was present to know
when to issue the next retry (added in 7.66.0).

If --retry is provided several times, the last set value is used.

Example:
.nf
 curl --retry 7 https://example.com
.fi

See also \fI\-\-retry\-max\-time\fP.
.IP "\-\-retry\-all\-errors"
Retry on any error. This option is used together with \fI\-\-retry\fP.

This option is the "sledgehammer" of retrying. Do not use this option by
default (for example in your \fBcurlrc\fP), there may be unintended consequences
such as sending or receiving duplicate data. Do not use with redirected input
or output. You might be better off handling your unique problems in a shell
script. Please read the example below.

\fBWARNING\fP: For server compatibility curl attempts to retry failed flaky
transfers as close as possible to how they were started, but this is not
possible with redirected input or output. For example, before retrying it
removes output data from a failed partial transfer that was written to an
output file. However this is not true of data redirected to a | pipe or >
file, which are not reset. We strongly suggest you do not parse or record
output via redirect in combination with this option, since you may receive
duplicate data.

By default curl does not return error for transfers with an HTTP response code
that indicates an HTTP error, if the transfer was successful. For example, if
a server replies 404 Not Found and the reply is fully received then that is
not an error. When \fI\-\-retry\fP is used then curl retries on some HTTP response
codes that indicate transient HTTP errors, but that does not include most 4xx
response codes such as 404. If you want to retry on all response codes that
indicate HTTP errors (4xx and 5xx) then combine with \fI\-f, \-\-fail\fP.

Providing --retry-all-errors multiple times has no extra effect.
Disable it again with \-\-no-retry-all-errors.

Example:
.nf
 curl --retry 5 --retry-all-errors https://example.com
.fi

Added in 7.71.0. See also \fI\-\-retry\fP.
.IP "\-\-retry\-connrefused"
In addition to the other conditions, consider ECONNREFUSED as a transient
error too for \fI\-\-retry\fP. This option is used together with \fI\-\-retry\fP.

Providing --retry-connrefused multiple times has no extra effect.
Disable it again with \-\-no-retry-connrefused.

Example:
.nf
 curl --retry-connrefused --retry 7 https://example.com
.fi

See also \fI\-\-retry\fP and \fI\-\-retry\-all\-errors\fP.
.IP "\-\-retry\-delay <seconds>"
Make curl sleep this amount of time before each retry when a transfer has
failed with a transient error (it changes the default backoff time algorithm
between retries). This option is only interesting if \fI\-\-retry\fP is also
used. Setting this delay to zero makes curl use the default backoff time.

If --retry-delay is provided several times, the last set value is used.

Example:
.nf
 curl --retry-delay 5 --retry 7 https://example.com
.fi

See also \fI\-\-retry\fP.
.IP "\-\-retry\-max\-time <seconds>"
The retry timer is reset before the first transfer attempt. Retries are done
as usual (see \fI\-\-retry\fP) as long as the timer has not reached this given
limit. Notice that if the timer has not reached the limit, the request is
made and while performing, it may take longer than this given time period. To
limit a single request\(aqs maximum time, use \fI\-m, \-\-max\-time\fP. Set this option to zero
to not timeout retries.

If --retry-max-time is provided several times, the last set value is used.

Example:
.nf
 curl --retry-max-time 30 --retry 10 https://example.com
.fi

See also \fI\-\-retry\fP.
.IP "\-\-sasl\-authzid <identity>"
Use this authorization identity (\fBauthzid\fP), during SASL PLAIN
authentication, in addition to the authentication identity (\fBauthcid\fP) as
specified by \fI\-u, \-\-user\fP.

If the option is not specified, the server derives the \fBauthzid\fP from the
\fBauthcid\fP, but if specified, and depending on the server implementation, it
may be used to access another user\(aqs inbox, that the user has been granted
access to, or a shared mailbox for example.

If --sasl-authzid is provided several times, the last set value is used.

Example:
.nf
 curl --sasl-authzid zid imap://example.com/
.fi

Added in 7.66.0. See also \fI\-\-login\-options\fP.
.IP "\-\-sasl\-ir"
Enable initial response in SASL authentication.

Providing --sasl-ir multiple times has no extra effect.
Disable it again with \-\-no-sasl-ir.

Example:
.nf
 curl --sasl-ir imap://example.com/
.fi

See also \fI\-\-sasl\-authzid\fP.
.IP "\-\-service\-name <name>"
Set the service name for SPNEGO.

If --service-name is provided several times, the last set value is used.

Example:
.nf
 curl --service-name sockd/server https://example.com
.fi

See also \fI\-\-negotiate\fP and \fI\-\-proxy\-service\-name\fP.
.IP "\-S, \-\-show\-error"
When used with \fI\-s, \-\-silent\fP, it makes curl show an error message if it fails.

This option is global and does not need to be specified for each use of --next.

Providing --show-error multiple times has no extra effect.
Disable it again with \-\-no-show-error.

Example:
.nf
 curl --show-error --silent https://example.com
.fi

See also \fI\-\-no\-progress\-meter\fP.
.IP "\-s, \-\-silent"
Silent or quiet mode. Do not show progress meter or error messages. Makes Curl
mute. It still outputs the data you ask for, potentially even to the
terminal/stdout unless you redirect it.

Use \fI\-S, \-\-show\-error\fP in addition to this option to disable progress meter but
still show error messages.

Providing --silent multiple times has no extra effect.
Disable it again with \-\-no-silent.

Example:
.nf
 curl -s https://example.com
.fi

See also \fI-v, \-\-verbose\fP, \fI\-\-stderr\fP and \fI\-\-no\-progress\-meter\fP.
.IP "\-\-socks4 <host[:port]>"
Use the specified SOCKS4 proxy. If the port number is not specified, it is
assumed at port 1080. Using this socket type make curl resolve the hostname
and passing the address on to the proxy.

To specify proxy on a unix domain socket, use localhost for host, e.g.
\&"socks4://localhost/path/to/socket.sock"

This option overrides any previous use of \fI\-x, \-\-proxy\fP, as they are mutually
exclusive.

This option is superfluous since you can specify a socks4 proxy with \fI\-x, \-\-proxy\fP
using a socks4:// protocol prefix.

\fI\-\-preproxy\fP can be used to specify a SOCKS proxy at the same time proxy is used
with an HTTP/HTTPS proxy. In such a case, curl first
connects to the SOCKS proxy and then connects (through SOCKS) to the HTTP or
HTTPS proxy.

If --socks4 is provided several times, the last set value is used.

Example:
.nf
 curl --socks4 hostname:4096 https://example.com
.fi

See also \fI\-\-socks4a\fP, \fI\-\-socks5\fP and \fI\-\-socks5\-hostname\fP.
.IP "\-\-socks4a <host[:port]>"
Use the specified SOCKS4a proxy. If the port number is not specified, it is
assumed at port 1080. This asks the proxy to resolve the hostname.

To specify proxy on a unix domain socket, use localhost for host, e.g.
\&"socks4a://localhost/path/to/socket.sock"

This option overrides any previous use of \fI\-x, \-\-proxy\fP, as they are mutually
exclusive.

This option is superfluous since you can specify a socks4a proxy with \fI\-x, \-\-proxy\fP
using a socks4a:// protocol prefix.

\fI\-\-preproxy\fP can be used to specify a SOCKS proxy at the same time \fI\-x, \-\-proxy\fP is
used with an HTTP/HTTPS proxy. In such a case, curl first
connects to the SOCKS proxy and then connects (through SOCKS) to the HTTP or
HTTPS proxy.

If --socks4a is provided several times, the last set value is used.

Example:
.nf
 curl --socks4a hostname:4096 https://example.com
.fi

See also \fI\-\-socks4\fP, \fI\-\-socks5\fP and \fI\-\-socks5\-hostname\fP.
.IP "\-\-socks5 <host[:port]>"
Use the specified SOCKS5 proxy \- but resolve the hostname locally. If the
port number is not specified, it is assumed at port 1080.

To specify proxy on a unix domain socket, use localhost for host, e.g.
\&"socks5://localhost/path/to/socket.sock"

This option overrides any previous use of \fI\-x, \-\-proxy\fP, as they are mutually
exclusive.

This option is superfluous since you can specify a socks5 proxy with \fI\-x, \-\-proxy\fP
using a socks5:// protocol prefix.

\fI\-\-preproxy\fP can be used to specify a SOCKS proxy at the same time \fI\-x, \-\-proxy\fP is
used with an HTTP/HTTPS proxy. In such a case, curl first
connects to the SOCKS proxy and then connects (through SOCKS) to the HTTP or
HTTPS proxy.

This option does not work with FTPS or LDAP.

If --socks5 is provided several times, the last set value is used.

Example:
.nf
 curl --socks5 proxy.example:7000 https://example.com
.fi

See also \fI\-\-socks5\-hostname\fP and \fI\-\-socks4a\fP.
.IP "\-\-socks5\-basic"
Use username/password authentication when connecting to a SOCKS5 proxy. The
username/password authentication is enabled by default. Use \fI\-\-socks5\-gssapi\fP to
force GSS\-API authentication to SOCKS5 proxies.

Providing --socks5-basic multiple times has no extra effect.

Example:
.nf
 curl --socks5-basic --socks5 hostname:4096 https://example.com
.fi

See also \fI\-\-socks5\fP.
.IP "\-\-socks5\-gssapi"
Use GSS\-API authentication when connecting to a SOCKS5 proxy. The GSS\-API
authentication is enabled by default (if curl is compiled with GSS\-API
support). Use \fI\-\-socks5\-basic\fP to force username/password authentication to
SOCKS5 proxies.

Providing --socks5-gssapi multiple times has no extra effect.
Disable it again with \-\-no-socks5-gssapi.

Example:
.nf
 curl --socks5-gssapi --socks5 hostname:4096 https://example.com
.fi

See also \fI\-\-socks5\fP.
.IP "\-\-socks5\-gssapi\-nec"
As part of the GSS\-API negotiation a protection mode is negotiated. RFC 1961
says in section 4.3/4.4 it should be protected, but the NEC reference
implementation does not. The option \fI\-\-socks5\-gssapi\-nec\fP allows the
unprotected exchange of the protection mode negotiation.

Providing --socks5-gssapi-nec multiple times has no extra effect.
Disable it again with \-\-no-socks5-gssapi-nec.

Example:
.nf
 curl --socks5-gssapi-nec --socks5 hostname:4096 https://example.com
.fi

See also \fI\-\-socks5\fP.
.IP "\-\-socks5\-gssapi\-service <name>"
Set the service name for a socks server. Default is \fBrcmd/server\-fqdn\fP.

If --socks5-gssapi-service is provided several times, the last set value is used.

Example:
.nf
 curl --socks5-gssapi-service sockd --socks5 hostname:4096 https://example.com
.fi

See also \fI\-\-socks5\fP.
.IP "\-\-socks5\-hostname <host[:port]>"
Use the specified SOCKS5 proxy (and let the proxy resolve the hostname). If
the port number is not specified, it is assumed at port 1080.

To specify proxy on a unix domain socket, use localhost for host, e.g.
\&"socks5h://localhost/path/to/socket.sock"

This option overrides any previous use of \fI\-x, \-\-proxy\fP, as they are mutually
exclusive.

This option is superfluous since you can specify a socks5 hostname proxy with
\fI\-x, \-\-proxy\fP using a socks5h:// protocol prefix.

\fI\-\-preproxy\fP can be used to specify a SOCKS proxy at the same time \fI\-x, \-\-proxy\fP is
used with an HTTP/HTTPS proxy. In such a case, curl first
connects to the SOCKS proxy and then connects (through SOCKS) to the HTTP or
HTTPS proxy.

If --socks5-hostname is provided several times, the last set value is used.

Example:
.nf
 curl --socks5-hostname proxy.example:7000 https://example.com
.fi

See also \fI\-\-socks5\fP and \fI\-\-socks4a\fP.
.IP "\-Y, \-\-speed\-limit <speed>"
If a transfer is slower than this set speed (in bytes per second) for a given
number of seconds, it gets aborted. The time period is set with \fI\-y, \-\-speed\-time\fP
and is 30 seconds by default.

If --speed-limit is provided several times, the last set value is used.

Example:
.nf
 curl --speed-limit 300 --speed-time 10 https://example.com
.fi

See also \fI-y, \-\-speed\-time\fP, \fI\-\-limit\-rate\fP and \fI-m, \-\-max\-time\fP.
.IP "\-y, \-\-speed\-time <seconds>"
If a transfer runs slower than speed\-limit bytes per second during a
speed\-time period, the transfer is aborted. If speed\-time is used, the default
speed\-limit is 1 unless set with \fI\-Y, \-\-speed\-limit\fP.

This option controls transfers (in both directions) but does not affect slow
connects etc. If this is a concern for you, try the \fI\-\-connect\-timeout\fP option.

If --speed-time is provided several times, the last set value is used.

Example:
.nf
 curl --speed-limit 300 --speed-time 10 https://example.com
.fi

See also \fI-Y, \-\-speed\-limit\fP and \fI\-\-limit\-rate\fP.
.IP "\-\-ssl"
(FTP IMAP POP3 SMTP LDAP) Warning: this is considered an insecure option. Consider using \fI\-\-ssl\-reqd\fP
instead to be sure curl upgrades to a secure connection.

Try to use SSL/TLS for the connection \- often referred to as STARTTLS or STLS
because of the involved commands. Reverts to a non\-secure connection if the
server does not support SSL/TLS. See also \fI\-\-ftp\-ssl\-control\fP and \fI\-\-ssl\-reqd\fP for
different levels of encryption required.

This option is handled in LDAP (added in 7.81.0). It is fully supported by the
OpenLDAP backend and ignored by the generic ldap backend.

Please note that a server may close the connection if the negotiation does
not succeed.

This option was formerly known as \fI\-\-ftp\-ssl\fP. That option
name can still be used but might be removed in a future version.

Providing --ssl multiple times has no extra effect.
Disable it again with \-\-no-ssl.

Example:
.nf
 curl --ssl pop3://example.com/
.fi

See also \fI\-\-ssl\-reqd\fP, \fI-k, \-\-insecure\fP and \fI\-\-ciphers\fP.
.IP "\-\-ssl\-allow\-beast"
(TLS) Do not work around a security flaw in the TLS1.0 protocol known as BEAST. If
this option is not used, the TLS layer may use workarounds known to cause
interoperability problems with some older server implementations.

This option only changes how curl does TLS 1.0 and has no effect on later TLS
versions.

\fBWARNING\fP: this option loosens the TLS security, and by using this flag you
ask for exactly that.

Providing --ssl-allow-beast multiple times has no extra effect.
Disable it again with \-\-no-ssl-allow-beast.

Example:
.nf
 curl --ssl-allow-beast https://example.com
.fi

See also \fI\-\-proxy\-ssl\-allow\-beast\fP and \fI-k, \-\-insecure\fP.
.IP "\-\-ssl\-auto\-client\-cert"
(TLS) (Schannel) Automatically locate and use a client certificate for
authentication, when requested by the server. Since the server can request any
certificate that supports client authentication in the OS certificate store it
could be a privacy violation and unexpected.

Providing --ssl-auto-client-cert multiple times has no extra effect.
Disable it again with \-\-no-ssl-auto-client-cert.

Example:
.nf
 curl --ssl-auto-client-cert https://example.com
.fi

Added in 7.77.0. See also \fI\-\-proxy\-ssl\-auto\-client\-cert\fP.
.IP "\-\-ssl\-no\-revoke"
(TLS) (Schannel) Disable certificate revocation checks. WARNING: this option loosens
the SSL security, and by using this flag you ask for exactly that.

Providing --ssl-no-revoke multiple times has no extra effect.
Disable it again with \-\-no-ssl-no-revoke.

Example:
.nf
 curl --ssl-no-revoke https://example.com
.fi

See also \fI\-\-crlfile\fP.
.IP "\-\-ssl\-reqd"
(FTP IMAP POP3 SMTP LDAP) Require SSL/TLS for the connection \- often referred to as STARTTLS or STLS
because of the involved commands. Terminates the connection if the transfer
cannot be upgraded to use SSL/TLS.

This option is handled in LDAP (added in 7.81.0). It is fully supported by the
OpenLDAP backend and rejected by the generic ldap backend if explicit TLS is
required.

This option is unnecessary if you use a URL scheme that in itself implies
immediate and implicit use of TLS, like for FTPS, IMAPS, POP3S, SMTPS and
LDAPS. Such a transfer always fails if the TLS handshake does not work.

This option was formerly known as \fI\-\-ftp\-ssl\-reqd\fP.

Providing --ssl-reqd multiple times has no extra effect.
Disable it again with \-\-no-ssl-reqd.

Example:
.nf
 curl --ssl-reqd ftp://example.com
.fi

See also \fI\-\-ssl\fP and \fI-k, \-\-insecure\fP.
.IP "\-\-ssl\-revoke\-best\-effort"
(TLS) (Schannel) Ignore certificate revocation checks when they failed due to
missing/offline distribution points for the revocation check lists.

Providing --ssl-revoke-best-effort multiple times has no extra effect.
Disable it again with \-\-no-ssl-revoke-best-effort.

Example:
.nf
 curl --ssl-revoke-best-effort https://example.com
.fi

Added in 7.70.0. See also \fI\-\-crlfile\fP and \fI-k, \-\-insecure\fP.
.IP "\-2, \-\-sslv2"
(SSL) This option previously asked curl to use SSLv2, but is now ignored
(added in 7.77.0). SSLv2 is widely considered insecure (see RFC 6176).

Providing --sslv2 multiple times has no extra effect.

Example:
.nf
 curl --sslv2 https://example.com
.fi

\fI-2, \-\-sslv2\fP requires that libcurl is built to support TLS.
This option is mutually exclusive with \fI-3, \-\-sslv3\fP, \fI-1, \-\-tlsv1\fP, \fI\-\-tlsv1.1\fP and \fI\-\-tlsv1.2\fP.
See also \fI\-\-http1.1\fP and \fI\-\-http2\fP.
.IP "\-3, \-\-sslv3"
(SSL) This option previously asked curl to use SSLv3, but is now ignored
(added in 7.77.0). SSLv3 is widely considered insecure (see RFC 7568).

Providing --sslv3 multiple times has no extra effect.

Example:
.nf
 curl --sslv3 https://example.com
.fi

\fI-3, \-\-sslv3\fP requires that libcurl is built to support TLS.
This option is mutually exclusive with \fI-2, \-\-sslv2\fP, \fI-1, \-\-tlsv1\fP, \fI\-\-tlsv1.1\fP and \fI\-\-tlsv1.2\fP.
See also \fI\-\-http1.1\fP and \fI\-\-http2\fP.
.IP "\-\-stderr <file>"
Redirect all writes to stderr to the specified file instead. If the filename
is a plain \(aq\-\(aq, it is instead written to stdout.

This option is global and does not need to be specified for each use of --next.

If --stderr is provided several times, the last set value is used.

Example:
.nf
 curl --stderr output.txt https://example.com
.fi

See also \fI-v, \-\-verbose\fP and \fI-s, \-\-silent\fP.
.IP "\-\-styled\-output"
Enable automatic use of bold font styles when writing HTTP headers to the
terminal. Use \fI\-\-no\-styled\-output\fP to switch them off.

Styled output requires a terminal that supports bold fonts. This feature is
not present on curl for Windows due to lack of this capability.

This option is global and does not need to be specified for each use of --next.

Providing --styled-output multiple times has no extra effect.
Disable it again with \-\-no-styled-output.

Example:
.nf
 curl --styled-output -I https://example.com
.fi

Added in 7.61.0. See also \fI-I, \-\-head\fP and \fI-v, \-\-verbose\fP.
.IP "\-\-suppress\-connect\-headers"
When \fI\-p, \-\-proxytunnel\fP is used and a CONNECT request is made do not output proxy
CONNECT response headers. This option is meant to be used with \fI\-D, \-\-dump\-header\fP or
\fI\-i, \-\-include\fP which are used to show protocol headers in the output. It has no
effect on debug options such as \fI\-v, \-\-verbose\fP or \fI\-\-trace\fP, or any statistics.

Providing --suppress-connect-headers multiple times has no extra effect.
Disable it again with \-\-no-suppress-connect-headers.

Example:
.nf
 curl --suppress-connect-headers --include -x proxy https://example.com
.fi

See also \fI-D, \-\-dump\-header\fP, \fI-i, \-\-include\fP and \fI-p, \-\-proxytunnel\fP.
.IP "\-\-tcp\-fastopen"
Enable use of TCP Fast Open (RFC 7413). TCP Fast Open is a TCP extension that
allows data to get sent earlier over the connection (before the final
handshake ACK) if the client and server have been connected previously.

Providing --tcp-fastopen multiple times has no extra effect.
Disable it again with \-\-no-tcp-fastopen.

Example:
.nf
 curl --tcp-fastopen https://example.com
.fi

See also \fI\-\-false\-start\fP.
.IP "\-\-tcp\-nodelay"
Turn on the TCP_NODELAY option. See the \fIcurl_easy_setopt(3)\fP man page for
details about this option.

curl sets this option by default and you need to explicitly switch it off if
you do not want it on.

Providing --tcp-nodelay multiple times has no extra effect.
Disable it again with \-\-no-tcp-nodelay.

Example:
.nf
 curl --tcp-nodelay https://example.com
.fi

See also \fI-N, \-\-no\-buffer\fP.
.IP "\-t, \-\-telnet\-option <opt=val>"
Pass options to the telnet protocol. Supported options are:
.RS
.IP TTYPE=<term>
Sets the terminal type.
.IP "XDISPLOC=<X display>"
Sets the X display location.
.IP NEW_ENV=<var,val>
Sets an environment variable.
.RE
.IP

--telnet-option can be used several times in a command line

Example:
.nf
 curl -t TTYPE=vt100 telnet://example.com/
.fi

See also \fI-K, \-\-config\fP.
.IP "\-\-tftp\-blksize <value>"
(TFTP) Set the TFTP \fBBLKSIZE\fP option (must be 512 or larger). This is the block
size that curl tries to use when transferring data to or from a TFTP
server. By default 512 bytes are used.

If --tftp-blksize is provided several times, the last set value is used.

Example:
.nf
 curl --tftp-blksize 1024 tftp://example.com/file
.fi

See also \fI\-\-tftp\-no\-options\fP.
.IP "\-\-tftp\-no\-options"
(TFTP) Do not to send TFTP options requests. This improves interop with some legacy
servers that do not acknowledge or properly implement TFTP options. When this
option is used \fI\-\-tftp\-blksize\fP is ignored.

Providing --tftp-no-options multiple times has no extra effect.
Disable it again with \-\-no-tftp-no-options.

Example:
.nf
 curl --tftp-no-options tftp://192.168.0.1/
.fi

See also \fI\-\-tftp\-blksize\fP.
.IP "\-z, \-\-time\-cond <time>"
(HTTP FTP) Request a file that has been modified later than the given time and date, or
one that has been modified before that time. The date expression can be all
sorts of date strings or if it does not match any internal ones, it is treated
as a filename and curl tries to get the modification date (mtime) from that
file instead. See the \fIcurl_getdate(3)\fP man pages for date expression details.

Start the date expression with a dash (\-) to make it request for a document
that is older than the given date/time, default is a document that is newer
than the specified date/time.

If provided a non\-existing file, curl outputs a warning about that fact and
proceeds to do the transfer without a time condition.

If --time-cond is provided several times, the last set value is used.

Examples:
.nf
 curl -z "Wed 01 Sep 2021 12:18:00" https://example.com
 curl -z "-Wed 01 Sep 2021 12:18:00" https://example.com
 curl -z file https://example.com
.fi

See also \fI\-\-etag\-compare\fP and \fI-R, \-\-remote\-time\fP.
.IP "\-\-tls\-max <VERSION>"
(TLS) VERSION defines maximum supported TLS version. The minimum acceptable version
is set by tlsv1.0, tlsv1.1, tlsv1.2 or tlsv1.3.

If the connection is done without TLS, this option has no effect. This
includes QUIC\-using (HTTP/3) transfers.
.RS
.IP default
Use up to recommended TLS version.
.IP 1.0
Use up to TLSv1.0.
.IP 1.1
Use up to TLSv1.1.
.IP 1.2
Use up to TLSv1.2.
.IP 1.3
Use up to TLSv1.3.
.RE
.IP

If --tls-max is provided several times, the last set value is used.

Examples:
.nf
 curl --tls-max 1.2 https://example.com
 curl --tls-max 1.3 --tlsv1.2 https://example.com
.fi

\fI\-\-tls\-max\fP requires that libcurl is built to support TLS.
See also \fI\-\-tlsv1.0\fP, \fI\-\-tlsv1.1\fP, \fI\-\-tlsv1.2\fP and \fI\-\-tlsv1.3\fP.
.IP "\-\-tls13\-ciphers <list>"
(TLS) Specifies which cipher suites to use in the connection if it negotiates TLS
1.3. The list of ciphers suites must specify valid ciphers. Read up on TLS 1.3
cipher suite details on this URL:

https://curl.se/docs/ssl\-ciphers.html

This option is currently used only when curl is built to use OpenSSL 1.1.1 or
later, or Schannel. If you are using a different SSL backend you can try
setting TLS 1.3 cipher suites by using the \fI\-\-ciphers\fP option.

If --tls13-ciphers is provided several times, the last set value is used.

Example:
.nf
 curl --tls13-ciphers TLS_AES_128_GCM_SHA256 https://example.com
.fi

Added in 7.61.0. See also \fI\-\-ciphers\fP, \fI\-\-curves\fP and \fI\-\-proxy\-tls13\-ciphers\fP.
.IP "\-\-tlsauthtype <type>"
(TLS) Set TLS authentication type. Currently, the only supported option is "SRP",
for TLS\-SRP (RFC 5054). If \fI\-\-tlsuser\fP and \fI\-\-tlspassword\fP are specified but
\fI\-\-tlsauthtype\fP is not, then this option defaults to "SRP". This option works
only if the underlying libcurl is built with TLS\-SRP support, which requires
OpenSSL or GnuTLS with TLS\-SRP support.

If --tlsauthtype is provided several times, the last set value is used.

Example:
.nf
 curl --tlsauthtype SRP https://example.com
.fi

See also \fI\-\-tlsuser\fP.
.IP "\-\-tlspassword <string>"
(TLS) Set password to use with the TLS authentication method specified with
\fI\-\-tlsauthtype\fP. Requires that \fI\-\-tlsuser\fP is set.

This option does not work with TLS 1.3.

If --tlspassword is provided several times, the last set value is used.

Example:
.nf
 curl --tlspassword pwd --tlsuser user https://example.com
.fi

See also \fI\-\-tlsuser\fP.
.IP "\-\-tlsuser <name>"
(TLS) Set username for use with the TLS authentication method specified with
\fI\-\-tlsauthtype\fP. Requires that \fI\-\-tlspassword\fP also is set.

This option does not work with TLS 1.3.

If --tlsuser is provided several times, the last set value is used.

Example:
.nf
 curl --tlspassword pwd --tlsuser user https://example.com
.fi

See also \fI\-\-tlspassword\fP.
.IP "\-1, \-\-tlsv1"
(TLS) Use at least TLS version 1.x when negotiating with a remote TLS server. That
means TLS version 1.0 or higher

Providing --tlsv1 multiple times has no extra effect.

Example:
.nf
 curl --tlsv1 https://example.com
.fi

\fI-1, \-\-tlsv1\fP requires that libcurl is built to support TLS.
This option is mutually exclusive with \fI\-\-tlsv1.1\fP, \fI\-\-tlsv1.2\fP and \fI\-\-tlsv1.3\fP.
See also \fI\-\-http1.1\fP and \fI\-\-http2\fP.
.IP "\-\-tlsv1.0"
(TLS) Forces curl to use TLS version 1.0 or later when connecting to a remote TLS server.

In old versions of curl this option was documented to allow _only_ TLS 1.0.
That behavior was inconsistent depending on the TLS library. Use \fI\-\-tls\-max\fP if
you want to set a maximum TLS version.

Providing --tlsv1.0 multiple times has no extra effect.

Example:
.nf
 curl --tlsv1.0 https://example.com
.fi

See also \fI\-\-tlsv1.3\fP.
.IP "\-\-tlsv1.1"
(TLS) Forces curl to use TLS version 1.1 or later when connecting to a remote TLS server.

In old versions of curl this option was documented to allow _only_ TLS 1.1.
That behavior was inconsistent depending on the TLS library. Use \fI\-\-tls\-max\fP if
you want to set a maximum TLS version.

Providing --tlsv1.1 multiple times has no extra effect.

Example:
.nf
 curl --tlsv1.1 https://example.com
.fi

See also \fI\-\-tlsv1.3\fP and \fI\-\-tls\-max\fP.
.IP "\-\-tlsv1.2"
(TLS) Forces curl to use TLS version 1.2 or later when connecting to a remote TLS server.

In old versions of curl this option was documented to allow _only_ TLS 1.2.
That behavior was inconsistent depending on the TLS library. Use \fI\-\-tls\-max\fP if
you want to set a maximum TLS version.

Providing --tlsv1.2 multiple times has no extra effect.

Example:
.nf
 curl --tlsv1.2 https://example.com
.fi

See also \fI\-\-tlsv1.3\fP and \fI\-\-tls\-max\fP.
.IP "\-\-tlsv1.3"
(TLS) Forces curl to use TLS version 1.3 or later when connecting to a remote TLS
server.

If the connection is done without TLS, this option has no effect. This
includes QUIC\-using (HTTP/3) transfers.

Note that TLS 1.3 is not supported by all TLS backends.

Providing --tlsv1.3 multiple times has no extra effect.

Example:
.nf
 curl --tlsv1.3 https://example.com
.fi

See also \fI\-\-tlsv1.2\fP and \fI\-\-tls\-max\fP.
.IP "\-\-tr\-encoding"
(HTTP) Request a compressed Transfer\-Encoding response using one of the algorithms
curl supports, and uncompress the data while receiving it.

Providing --tr-encoding multiple times has no extra effect.
Disable it again with \-\-no-tr-encoding.

Example:
.nf
 curl --tr-encoding https://example.com
.fi

See also \fI\-\-compressed\fP.
.IP "\-\-trace <file>"
Save a full trace dump of all incoming and outgoing data, including
descriptive information, in the given output file. Use "\-" as filename to have
the output sent to stdout. Use "%" as filename to have the output sent to
stderr.

Note that verbose output of curl activities and network traffic might contain
sensitive data, including usernames, credentials or secret data content. Be
aware and be careful when sharing trace logs with others.

This option is global and does not need to be specified for each use of --next.

If --trace is provided several times, the last set value is used.

Example:
.nf
 curl --trace log.txt https://example.com
.fi

This option is mutually exclusive with \fI-v, \-\-verbose\fP and \fI\-\-trace\-ascii\fP.
See also \fI\-\-trace\-ascii\fP, \fI\-\-trace\-config\fP, \fI\-\-trace\-ids\fP and \fI\-\-trace\-time\fP.
.IP "\-\-trace\-ascii <file>"
Save a full trace dump of all incoming and outgoing data, including
descriptive information, in the given output file. Use "\-" as filename to have
the output sent to stdout. Use "%" as filename to send the output to stderr.

This is similar to \fI\-\-trace\fP, but leaves out the hex part and only shows the
ASCII part of the dump. It makes smaller output that might be easier to read
for untrained humans.

Note that verbose output of curl activities and network traffic might contain
sensitive data, including usernames, credentials or secret data content. Be
aware and be careful when sharing trace logs with others.

This option is global and does not need to be specified for each use of --next.

If --trace-ascii is provided several times, the last set value is used.

Example:
.nf
 curl --trace-ascii log.txt https://example.com
.fi

This option is mutually exclusive with \fI\-\-trace\fP and \fI-v, \-\-verbose\fP.
See also \fI-v, \-\-verbose\fP and \fI\-\-trace\fP.
.IP "\-\-trace\-config <string>"
Set configuration for trace output. A comma\-separated list of components where
detailed output can be made available from. Names are case\-insensitive.
Specify \(aqall\(aq to enable all trace components.

In addition to trace component names, specify "ids" and "time" to avoid extra
\fI\-\-trace\-ids\fP or \fI\-\-trace\-time\fP parameters.

See the \fIcurl_global_trace(3)\fP man page for more details.

This option is global and does not need to be specified for each use of --next.

--trace-config can be used several times in a command line

Example:
.nf
 curl --trace-config ids,http/2 https://example.com
.fi

Added in 8.3.0. See also \fI-v, \-\-verbose\fP and \fI\-\-trace\fP.
.IP "\-\-trace\-ids"
Prepends the transfer and connection identifiers to each trace or verbose line that curl displays.

This option is global and does not need to be specified for each use of --next.

Providing --trace-ids multiple times has no extra effect.
Disable it again with \-\-no-trace-ids.

Example:
.nf
 curl --trace-ids --trace-ascii output https://example.com
.fi

Added in 8.2.0. See also \fI\-\-trace\fP and \fI-v, \-\-verbose\fP.
.IP "\-\-trace\-time"
Prepends a time stamp to each trace or verbose line that curl displays.

This option is global and does not need to be specified for each use of --next.

Providing --trace-time multiple times has no extra effect.
Disable it again with \-\-no-trace-time.

Example:
.nf
 curl --trace-time --trace-ascii output https://example.com
.fi

See also \fI\-\-trace\fP and \fI-v, \-\-verbose\fP.
.IP "\-\-unix\-socket <path>"
(HTTP) Connect through this Unix domain socket, instead of using the network.

If --unix-socket is provided several times, the last set value is used.

Example:
.nf
 curl --unix-socket socket-path https://example.com
.fi

See also \fI\-\-abstract\-unix\-socket\fP.
.IP "\-T, \-\-upload\-file <file>"
Upload the specified local file to the remote URL.

If there is no file part in the specified URL, curl appends the local file
name to the end of the URL before the operation starts. You must use a
trailing slash (/) on the last directory to prove to curl that there is no
filename or curl thinks that your last directory name is the remote filename
to use.

When putting the local filename at the end of the URL, curl ignores what is on
the left side of any slash (/) or backslash (\\) used in the filename and only
appends what is on the right side of the rightmost such character.

Use the filename "\-" (a single dash) to use stdin instead of a given file.
Alternately, the filename "." (a single period) may be specified instead of
\&"\-" to use stdin in non\-blocking mode to allow reading server output while
stdin is being uploaded.

If this option is used with an HTTP(S) URL, the PUT method is used.

You can specify one \fI\-T, \-\-upload\-file\fP for each URL on the command line. Each
\fI\-T, \-\-upload\-file\fP + URL pair specifies what to upload and to where. curl also
supports globbing of the \fI\-T, \-\-upload\-file\fP argument, meaning that you can upload
multiple files to a single URL by using the same URL globbing style supported
in the URL.

When uploading to an SMTP server: the uploaded data is assumed to be RFC 5322
formatted. It has to feature the necessary set of headers and mail body
formatted correctly by the user as curl does not transcode nor encode it
further in any way.

--upload-file is associated with a single URL. Use it once per URL when you use several URLs in a command line.

Examples:
.nf
 curl -T file https://example.com
 curl -T "img[1-1000].png" ftp://ftp.example.com/
 curl --upload-file "{file1,file2}" https://example.com
 curl -T file -T file2 https://example.com https://example.com
.fi

See also \fI-G, \-\-get\fP, \fI-I, \-\-head\fP, \fI-X, \-\-request\fP and \fI-d, \-\-data\fP.
.IP "\-\-url <url>"
Specify a URL to fetch.

If the given URL is missing a scheme name (such as "http://" or "ftp://" etc)
then curl makes a guess based on the host. If the outermost subdomain name
matches DICT, FTP, IMAP, LDAP, POP3 or SMTP then that protocol is used,
otherwise HTTP is used. Guessing can be avoided by providing a full URL
including the scheme, or disabled by setting a default protocol, see
\fI\-\-proto\-default\fP for details.

To control where this URL is written, use the \fI\-o, \-\-output\fP or the \fI\-O, \-\-remote\-name\fP
options.

\fBWARNING\fP: On Windows, particular "file://" accesses can be converted to
network accesses by the operating system. Beware!

--url can be used several times in a command line

Example:
.nf
 curl --url https://example.com
.fi

See also \fI-:, \-\-next\fP and \fI-K, \-\-config\fP.
.IP "\-\-url\-query <data>"
(all) Add a piece of data, usually a name + value pair, to the end of the URL query
part. The syntax is identical to that used for \fI\-\-data\-urlencode\fP with one
extension:

If the argument starts with a \(aq+\(aq (plus), the rest of the string is provided
as\-is unencoded.

The query part of a URL is the one following the question mark on the right
end.

--url-query can be used several times in a command line

Examples:
.nf
 curl --url-query name=val https://example.com
 curl --url-query =encodethis http://example.net/foo
 curl --url-query name@file https://example.com
 curl --url-query @fileonly https://example.com
 curl --url-query "+name=%20foo" https://example.com
.fi

Added in 7.87.0. See also \fI\-\-data\-urlencode\fP and \fI-G, \-\-get\fP.
.IP "\-B, \-\-use\-ascii"
(FTP LDAP) Enable ASCII transfer mode. For FTP, this can also be enforced by using a URL
that ends with ";type=A". This option causes data sent to stdout to be in text
mode for win32 systems.

Providing --use-ascii multiple times has no extra effect.
Disable it again with \-\-no-use-ascii.

Example:
.nf
 curl -B ftp://example.com/README
.fi

See also \fI\-\-crlf\fP and \fI\-\-data\-ascii\fP.
.IP "\-u, \-\-user <user:password>"
Specify the username and password to use for server authentication. Overrides
\fI\-n, \-\-netrc\fP and \fI\-\-netrc\-optional\fP.

If you simply specify the username, curl prompts for a password.

The username and passwords are split up on the first colon, which makes it
impossible to use a colon in the username with this option. The password can,
still.

On systems where it works, curl hides the given option argument from process
listings. This is not enough to protect credentials from possibly getting seen
by other users on the same system as they still are visible for a moment
before cleared. Such sensitive data should be retrieved from a file instead or
similar and never used in clear text in a command line.

When using Kerberos V5 with a Windows based server you should include the
Windows domain name in the username, in order for the server to successfully
obtain a Kerberos Ticket. If you do not, then the initial authentication
handshake may fail.

When using NTLM, the username can be specified simply as the username, without
the domain, if there is a single domain and forest in your setup for example.

To specify the domain name use either Down\-Level Logon Name or UPN (User
Principal Name) formats. For example, EXAMPLE\\user and user@example.com
respectively.

If you use a Windows SSPI\-enabled curl binary and perform Kerberos V5,
Negotiate, NTLM or Digest authentication then you can tell curl to select the
username and password from your environment by specifying a single colon with
this option: "\-u :".

If --user is provided several times, the last set value is used.

Example:
.nf
 curl -u user:secret https://example.com
.fi

See also \fI-n, \-\-netrc\fP and \fI-K, \-\-config\fP.
.IP "\-A, \-\-user\-agent <name>"
(HTTP) Specify the User\-Agent string to send to the HTTP server. To encode blanks in
the string, surround the string with single quote marks. This header can also
be set with the \fI\-H, \-\-header\fP or the \fI\-\-proxy\-header\fP options.

If you give an empty argument to \fI\-A, \-\-user\-agent\fP (""), it removes the header
completely from the request. If you prefer a blank header, you can set it to a
single space (" ").

If --user-agent is provided several times, the last set value is used.

Example:
.nf
 curl -A "Agent 007" https://example.com
.fi

See also \fI-H, \-\-header\fP and \fI\-\-proxy\-header\fP.
.IP "\-\-variable <[%]name=text/@file>"
Set a variable with "name=content" or "name@file" (where "file" can be stdin
if set to a single dash ("\-")). The name is a case sensitive identifier that
must consist of no other letters than a\-z, A\-Z, 0\-9 or underscore. The
specified content is then associated with this identifier.

Setting the same variable name again overwrites the old contents with the new.

The contents of a variable can be referenced in a later command line option
when that option name is prefixed with "\fI\-\-expand\-\fP", and the name is used as
\&"{{name}}".

\fI\-\-variable\fP can import environment variables into the name space. Opt to either
require the environment variable to be set or provide a default value for the
variable in case it is not already set.

\fI\-\-variable\fP %name imports the variable called "name" but exits with an error if
that environment variable is not already set. To provide a default value if
the environment variable is not set, use \fI\-\-variable\fP %name=content or
\fI\-\-variable\fP %name@content. Note that on some systems \- but not all \-
environment variables are case insensitive.

When expanding variables, curl supports a set of functions that can make the
variable contents more convenient to use. You apply a function to a variable
expansion by adding a colon and then list the desired functions in a
comma\-separated list that is evaluated in a left\-to\-right order. Variable
content holding null bytes that are not encoded when expanded, causes an
error.

Available functions:
.RS
.IP trim
removes all leading and trailing white space.
.IP json
outputs the content using JSON string quoting rules.
.IP url
shows the content URL (percent) encoded.
.IP b64
expands the variable base64 encoded
.RE
.IP

--variable can be used several times in a command line

Example:
.nf
 curl --variable name=smith --expand-url "https://example.com/{{name}}"
.fi

Added in 8.3.0. See also \fI-K, \-\-config\fP.
.IP "\-v, \-\-verbose"
Makes curl verbose during the operation. Useful for debugging and seeing
what\(aqs going on under the hood. A line starting with > means header data sent
by curl, < means header data received by curl that is hidden in normal cases,
and a line starting with * means additional info provided by curl.

If you only want HTTP headers in the output, \fI\-i, \-\-include\fP or \fI\-D, \-\-dump\-header\fP might
be more suitable options.

If you think this option still does not give you enough details, consider using
\fI\-\-trace\fP or \fI\-\-trace\-ascii\fP instead.

Note that verbose output of curl activities and network traffic might contain
sensitive data, including usernames, credentials or secret data content. Be
aware and be careful when sharing trace logs with others.

This option is global and does not need to be specified for each use of --next.

Providing --verbose multiple times has no extra effect.
Disable it again with \-\-no-verbose.

Example:
.nf
 curl --verbose https://example.com
.fi

This option is mutually exclusive with \fI\-\-trace\fP and \fI\-\-trace\-ascii\fP.
See also \fI-i, \-\-include\fP, \fI-s, \-\-silent\fP, \fI\-\-trace\fP and \fI\-\-trace\-ascii\fP.
.IP "\-V, \-\-version"
Displays information about curl and the libcurl version it uses.

The first line includes the full version of curl, libcurl and other 3rd party
libraries linked with the executable.

The second line (starts with "Release\-Date:") shows the release date.

The third line (starts with "Protocols:") shows all protocols that libcurl
reports to support.

The fourth line (starts with "Features:") shows specific features libcurl
reports to offer. Available features include:
.RS
.IP alt-svc
Support for the Alt\-Svc: header is provided.
.IP AsynchDNS
This curl uses asynchronous name resolves. Asynchronous name resolves can be
done using either the c\-ares or the threaded resolver backends.
.IP brotli
Support for automatic brotli compression over HTTP(S).
.IP CharConv
curl was built with support for character set conversions (like EBCDIC)
.IP Debug
This curl uses a libcurl built with Debug. This enables more error\-tracking
and memory debugging etc. For curl\-developers only!
.IP ECH
ECH support is present.
.IP gsasl
The built\-in SASL authentication includes extensions to support SCRAM because
libcurl was built with libgsasl.
.IP GSS-API
GSS\-API is supported.
.IP HSTS
HSTS support is present.
.IP HTTP2
HTTP/2 support has been built\-in.
.IP HTTP3
HTTP/3 support has been built\-in.
.IP HTTPS-proxy
This curl is built to support HTTPS proxy.
.IP IDN
This curl supports IDN \- international domain names.
.IP IPv6
You can use IPv6 with this.
.IP Kerberos
Kerberos V5 authentication is supported.
.IP Largefile
This curl supports transfers of large files, files larger than 2GB.
.IP libz
Automatic decompression (via gzip, deflate) of compressed files over HTTP is
supported.
.IP MultiSSL
This curl supports multiple TLS backends.
.IP NTLM
NTLM authentication is supported.
.IP NTLM_WB
NTLM delegation to winbind helper is supported.
.IP PSL
PSL is short for Public Suffix List and means that this curl has been built
with knowledge about "public suffixes".
.IP SPNEGO
SPNEGO authentication is supported.
.IP SSL
SSL versions of various protocols are supported, such as HTTPS, FTPS, POP3S
and so on.
.IP SSPI
SSPI is supported.
.IP TLS-SRP
SRP (Secure Remote Password) authentication is supported for TLS.
.IP TrackMemory
Debug memory tracking is supported.
.IP Unicode
Unicode support on Windows.
.IP UnixSockets
Unix sockets support is provided.
.IP zstd
Automatic decompression (via zstd) of compressed files over HTTP is supported.
.RE
.IP

Example:
.nf
 curl --version
.fi

See also \fI-h, \-\-help\fP and \fI-M, \-\-manual\fP.
.IP "\-\-vlan\-priority <priority>"
(All) Set VLAN priority as defined in IEEE 802.1Q.

This field is set on Ethernet level, and only works within a local network.

The valid range for <priority> is 0 to 7.

If --vlan-priority is provided several times, the last set value is used.

Example:
.nf
 curl --vlan-priority 4 https://example.com
.fi

Added in 8.9.0. See also \fI\-\-ip\-tos\fP.
.IP "\-w, \-\-write\-out <format>"
Make curl display information on stdout after a completed transfer. The format
is a string that may contain plain text mixed with any number of variables.
The format can be specified as a literal "string", or you can have curl read
the format from a file with "@filename" and to tell curl to read the format
from stdin you write "@\-".

The variables present in the output format are substituted by the value or
text that curl thinks fit, as described below. All variables are specified as
%{variable_name} and to output a normal % you just write them as %%. You can
output a newline by using \\n, a carriage return with \\r and a tab space with
\\t.

The output is by default written to standard output, but can be changed with
%{stderr} and %output{}.

Output HTTP headers from the most recent request by using \fI%header{name}\fP
where \fIname\fP is the case insensitive name of the header (without the trailing
colon). The header contents are exactly as sent over the network, with leading
and trailing whitespace trimmed (added in 7.84.0).

Select a specific target destination file to write the output to, by using
\fI%output{name}\fP (added in curl 8.3.0) where \fIname\fP is the full filename. The
output following that instruction is then written to that file. More than one
\fI%output{}\fP instruction can be specified in the same write\-out argument. If
the filename cannot be created, curl leaves the output destination to the one
used prior to the \fI%output{}\fP instruction. Use \fI%output{>>name}\fP to append
data to an existing file.

This output is done independently of if the file transfer was successful or
not.

If the specified action or output specified with this option fails in any way,
it does not make curl return a (different) error.

\fBNOTE:\fP On Windows, the %\-symbol is a special symbol used to expand
environment variables. In batch files, all occurrences of % must be doubled
when using this option to properly escape. If this option is used at the
command prompt then the % cannot be escaped and unintended expansion is
possible.

The variables available are:
.RS
.IP certs
Output the certificate chain with details. Supported only by the OpenSSL,
GnuTLS, Schannel and Secure Transport backends. (Added in 7.88.0)
.IP conn_id
The connection identifier last used by the transfer. The connection id is
unique number among all connections using the same connection cache.
(Added in 8.2.0)
.IP content_type
The Content\-Type of the requested document, if there was any.
.IP errormsg
The error message. (Added in 7.75.0)
.IP exitcode
The numerical exit code of the transfer. (Added in 7.75.0)
.IP filename_effective
The ultimate filename that curl writes out to. This is only meaningful if curl
is told to write to a file with the \fI\-O, \-\-remote\-name\fP or \fI\-o, \-\-output\fP option. It is
most useful in combination with the \fI\-J, \-\-remote\-header\-name\fP option.

.IP ftp_entry_path
The initial path curl ended up in when logging on to the remote FTP
server.
.IP header_json
A JSON object with all HTTP response headers from the recent transfer. Values
are provided as arrays, since in the case of multiple headers there can be
multiple values. (Added in 7.83.0)

The header names provided in lowercase, listed in order of appearance over the
wire. Except for duplicated headers. They are grouped on the first occurrence
of that header, each value is presented in the JSON array.
.IP http_code
The numerical response code that was found in the last retrieved HTTP(S) or
FTP(s) transfer.
.IP http_connect
The numerical code that was found in the last response (from a proxy) to a
curl CONNECT request.
.IP http_version
The http version that was effectively used.
.IP json
A JSON object with all available keys. (Added in 7.70.0)
.IP local_ip
The IP address of the local end of the most recently done connection \- can be
either IPv4 or IPv6.
.IP local_port
The local port number of the most recently done connection.
.IP method
The http method used in the most recent HTTP request. (Added in 7.72.0)
.IP num_certs
Number of server certificates received in the TLS handshake. Supported only by
the OpenSSL, GnuTLS, Schannel and Secure Transport backends.
(Added in 7.88.0)
.IP num_connects
Number of new connects made in the recent transfer.
.IP num_headers
The number of response headers in the most recent request (restarted at each
redirect). Note that the status line IS NOT a header. (Added in 7.73.0)
.IP num_redirects
Number of redirects that were followed in the request.
.IP num_retries
Number of retries actually performed when "\fI\-\-retry\fP" has been used.
(Added in 8.9.0)
.IP onerror
The rest of the output is only shown if the transfer returned a non\-zero error.
(Added in 7.75.0)
.IP proxy_ssl_verify_result
The result of the HTTPS proxy\(aqs SSL peer certificate verification that was
requested. 0 means the verification was successful.
.IP proxy_used
Returns 1 if the previous transfer used a proxy, otherwise 0. Useful to for
example determine if a "NOPROXY" pattern matched the hostname or not. (Added
in 8.7.0)
.IP redirect_url
When an HTTP request was made without \fI\-L, \-\-location\fP to follow redirects (or when
\fI\-\-max\-redirs\fP is met), this variable shows the actual URL a redirect
\fIwould\fP have gone to.
.IP referer
The Referer: header, if there was any. (Added in 7.76.0)
.IP remote_ip
The remote IP address of the most recently done connection \- can be either
IPv4 or IPv6.
.IP remote_port
The remote port number of the most recently done connection.
.IP response_code
The numerical response code that was found in the last transfer (formerly
known as "http_code").
.IP scheme
The URL scheme (sometimes called protocol) that was effectively used.
.IP size_download
The total amount of bytes that were downloaded. This is the size of the
body/data that was transferred, excluding headers.
.IP size_header
The total amount of bytes of the downloaded headers.
.IP size_request
The total amount of bytes that were sent in the HTTP request.
.IP size_upload
The total amount of bytes that were uploaded. This is the size of the
body/data that was transferred, excluding headers.
.IP speed_download
The average download speed that curl measured for the complete download. Bytes
per second.
.IP speed_upload
The average upload speed that curl measured for the complete upload. Bytes per
second.
.IP ssl_verify_result
The result of the SSL peer certificate verification that was requested. 0
means the verification was successful.
.IP stderr
From this point on, the \fI\-w, \-\-write\-out\fP output is written to standard
error. (Added in 7.63.0)
.IP stdout
From this point on, the \fI\-w, \-\-write\-out\fP output is written to standard output.
This is the default, but can be used to switch back after switching to stderr.
(Added in 7.63.0)
.IP time_appconnect
The time, in seconds, it took from the start until the SSL/SSH/etc
connect/handshake to the remote host was completed.
.IP time_connect
The time, in seconds, it took from the start until the TCP connect to the
remote host (or proxy) was completed.
.IP time_namelookup
The time, in seconds, it took from the start until the name resolving was
completed.
.IP time_pretransfer
The time, in seconds, it took from the start until the file transfer was just
about to begin. This includes all pre\-transfer commands and negotiations that
are specific to the particular protocol(s) involved.
.IP time_redirect
The time, in seconds, it took for all redirection steps including name lookup,
connect, pretransfer and transfer before the final transaction was
started. "time_redirect" shows the complete execution time for multiple
redirections.
.IP time_starttransfer
The time, in seconds, it took from the start until the first byte is received.
This includes time_pretransfer and also the time the server needed to calculate
the result.
.IP time_total
The total time, in seconds, that the full operation lasted.
.IP url
The URL that was fetched. (Added in 7.75.0)
.IP url.scheme
The scheme part of the URL that was fetched. (Added in 8.1.0)
.IP url.user
The user part of the URL that was fetched. (Added in 8.1.0)
.IP url.password
The password part of the URL that was fetched. (Added in 8.1.0)
.IP url.options
The options part of the URL that was fetched. (Added in 8.1.0)
.IP url.host
The host part of the URL that was fetched. (Added in 8.1.0)
.IP url.port
The port number of the URL that was fetched. If no port number was specified
and the URL scheme is known, that scheme\(aqs default port number is
shown. (Added in 8.1.0)
.IP url.path
The path part of the URL that was fetched. (Added in 8.1.0)
.IP url.query
The query part of the URL that was fetched. (Added in 8.1.0)
.IP url.fragment
The fragment part of the URL that was fetched. (Added in 8.1.0)
.IP url.zoneid
The zone id part of the URL that was fetched. (Added in 8.1.0)
.IP urle.scheme
The scheme part of the effective (last) URL that was fetched. (Added in 8.1.0)
.IP urle.user
The user part of the effective (last) URL that was fetched. (Added in 8.1.0)
.IP urle.password
The password part of the effective (last) URL that was fetched. (Added in 8.1.0)
.IP urle.options
The options part of the effective (last) URL that was fetched. (Added in 8.1.0)
.IP urle.host
The host part of the effective (last) URL that was fetched. (Added in 8.1.0)
.IP urle.port
The port number of the effective (last) URL that was fetched. If no port
number was specified, but the URL scheme is known, that scheme\(aqs default port
number is shown. (Added in 8.1.0)
.IP urle.path
The path part of the effective (last) URL that was fetched. (Added in 8.1.0)
.IP urle.query
The query part of the effective (last) URL that was fetched. (Added in 8.1.0)
.IP urle.fragment
The fragment part of the effective (last) URL that was fetched. (Added in 8.1.0)
.IP urle.zoneid
The zone id part of the effective (last) URL that was fetched. (Added in 8.1.0)
.IP urlnum
The URL index number of this transfer, 0\-indexed. Unglobbed URLs share the
same index number as the origin globbed URL. (Added in 7.75.0)
.IP url_effective
The URL that was fetched last. This is most meaningful if you have told curl
to follow location: headers.
.IP xfer_id
The numerical identifier of the last transfer done. \-1 if no transfer has been
started yet for the handle. The transfer id is unique among all transfers
performed using the same connection cache.
(Added in 8.2.0)
.RE
.IP

If --write-out is provided several times, the last set value is used.

Example:
.nf
 curl -w '%{response_code}\\n' https://example.com
.fi

See also \fI-v, \-\-verbose\fP and \fI-I, \-\-head\fP.
.IP "\-\-xattr"
When saving output to a file, tell curl to store file metadata in extended
file attributes. Currently, the URL is stored in the "xdg.origin.url"
attribute and, for HTTP, the content type is stored in the "mime_type"
attribute. If the file system does not support extended attributes, a warning
is issued.

Providing --xattr multiple times has no extra effect.
Disable it again with \-\-no-xattr.

Example:
.nf
 curl --xattr -o storage https://example.com
.fi

See also \fI-R, \-\-remote\-time\fP, \fI-w, \-\-write\-out\fP and \fI-v, \-\-verbose\fP.
.SH FILES
\fI~/.curlrc\fP

Default config file, see \fI\-K, \-\-config\fP for details.
.SH ENVIRONMENT
The environment variables can be specified in lower case or upper case. The
lower case version has precedence. "http_proxy" is an exception as it is only
available in lower case.

Using an environment variable to set the proxy has the same effect as using
the \fI\-x, \-\-proxy\fP option.
.IP "http_proxy [protocol://]<host>[:port]"
Sets the proxy server to use for HTTP.
.IP "HTTPS_PROXY [protocol://]<host>[:port]"
Sets the proxy server to use for HTTPS.
.IP "[url-protocol]_PROXY [protocol://]<host>[:port]"
Sets the proxy server to use for [url\-protocol], where the protocol is a
protocol that curl supports and as specified in a URL. FTP, FTPS, POP3, IMAP,
SMTP, LDAP, etc.
.IP "ALL_PROXY [protocol://]<host>[:port]"
Sets the proxy server to use if no protocol\-specific proxy is set.
.IP "NO_PROXY <comma-separated list of hosts/domains>"
list of hostnames that should not go through any proxy. If set to an asterisk
\(aq*\(aq only, it matches all hosts. Each name in this list is matched as either a
domain name which contains the hostname, or the hostname itself.

This environment variable disables use of the proxy even when specified with
the \fI\-x, \-\-proxy\fP option. That is
.nf

NO_PROXY=direct.example.com curl \-x http://proxy.example.com
http://direct.example.com
.fi

accesses the target URL directly, and
.nf

NO_PROXY=direct.example.com curl \-x http://proxy.example.com
http://somewhere.example.com
.fi

accesses the target URL through the proxy.

The list of hostnames can also be include numerical IP addresses, and IPv6
versions should then be given without enclosing brackets.

IP addresses can be specified using CIDR notation: an appended slash and
number specifies the number of "network bits" out of the address to use in the
comparison (added in 7.86.0). For example "192.168.0.0/16" would match all
addresses starting with "192.168".
.IP "APPDATA <dir>"
On Windows, this variable is used when trying to find the home directory. If
the primary home variable are all unset.
.IP "COLUMNS <terminal width>"
If set, the specified number of characters is used as the terminal width when
the alternative progress\-bar is shown. If not set, curl tries to figure it out
using other ways.
.IP "CURL_CA_BUNDLE <file>"
If set, it is used as the \fI\-\-cacert\fP value. This environment variable is ignored
if Schannel is used as the TLS backend.
.IP "CURL_HOME <dir>"
If set, is the first variable curl checks when trying to find its home
directory. If not set, it continues to check \fIXDG_CONFIG_HOME\fP
.IP "CURL_SSL_BACKEND <TLS backend>"
If curl was built with support for "MultiSSL", meaning that it has built\-in
support for more than one TLS backend, this environment variable can be set to
the case insensitive name of the particular backend to use when curl is
invoked. Setting a name that is not a built\-in alternative makes curl stay
with the default.

SSL backend names (case\-insensitive): \fBbearssl\fP, \fBgnutls\fP, \fBmbedtls\fP,
\fBopenssl\fP, \fBrustls\fP, \fBschannel\fP, \fBsecure\-transport\fP, \fBwolfssl\fP
.IP "HOME <dir>"
If set, this is used to find the home directory when that is needed. Like when
looking for the default .curlrc. \fICURL_HOME\fP and \fIXDG_CONFIG_HOME\fP
have preference.
.IP "QLOGDIR <directory name>"
If curl was built with HTTP/3 support, setting this environment variable to a
local directory makes curl produce \fBqlogs\fP in that directory, using file
names named after the destination connection id (in hex). Do note that these
files can become rather large. Works with the ngtcp2 and quiche QUIC backends.
.IP SHELL
Used on VMS when trying to detect if using a \fBDCL\fP or a \fBunix\fP shell.
.IP "SSL_CERT_DIR <dir>"
If set, it is used as the \fI\-\-capath\fP value. This environment variable is ignored
if Schannel is used as the TLS backend.
.IP "SSL_CERT_FILE <path>"
If set, it is used as the \fI\-\-cacert\fP value. This environment variable is ignored
if Schannel is used as the TLS backend.
.IP "SSLKEYLOGFILE <filename>"
If you set this environment variable to a filename, curl stores TLS secrets
from its connections in that file when invoked to enable you to analyze the
TLS traffic in real time using network analyzing tools such as Wireshark. This
works with the following TLS backends: OpenSSL, LibreSSL (TLS 1.2 max),
BoringSSL, GnuTLS and wolfSSL.
.IP "USERPROFILE <dir>"
On Windows, this variable is used when trying to find the home directory. If
the other, primary, variable are all unset. If set, curl uses the path
\fB"$USERPROFILE\\Application Data"\fP.
.IP "XDG_CONFIG_HOME <dir>"
If \fICURL_HOME\fP is not set, this variable is checked when looking for a
default .curlrc file.
.SH PROXY PROTOCOL PREFIXES
The proxy string may be specified with a protocol:// prefix to specify
alternative proxy protocols.

If no protocol is specified in the proxy string or if the string does not
match a supported one, the proxy is treated as an HTTP proxy.

The supported proxy protocol prefixes are as follows:
.IP http://
Makes it use it as an HTTP proxy. The default if no scheme prefix is used.
.IP https://
Makes it treated as an \fBHTTPS\fP proxy.
.IP socks4://
Makes it the equivalent of \fI\-\-socks4\fP
.IP socks4a://
Makes it the equivalent of \fI\-\-socks4a\fP
.IP socks5://
Makes it the equivalent of \fI\-\-socks5\fP
.IP socks5h://
Makes it the equivalent of \fI\-\-socks5\-hostname\fP
.SH EXIT CODES
There are a bunch of different error codes and their corresponding error
messages that may appear under error conditions. At the time of this writing,
the exit codes are:
.IP 0
Success. The operation completed successfully according to the instructions.
.IP 1
Unsupported protocol. This build of curl has no support for this protocol.
.IP 2
Failed to initialize.
.IP 3
URL malformed. The syntax was not correct.
.IP 4
A feature or option that was needed to perform the desired request was not
enabled or was explicitly disabled at build\-time. To make curl able to do
this, you probably need another build of libcurl.
.IP 5
Could not resolve proxy. The given proxy host could not be resolved.
.IP 6
Could not resolve host. The given remote host could not be resolved.
.IP 7
Failed to connect to host.
.IP 8
Weird server reply. The server sent data curl could not parse.
.IP 9
FTP access denied. The server denied login or denied access to the particular
resource or directory you wanted to reach. Most often you tried to change to a
directory that does not exist on the server.
.IP 10
FTP accept failed. While waiting for the server to connect back when an active
FTP session is used, an error code was sent over the control connection or
similar.
.IP 11
FTP weird PASS reply. Curl could not parse the reply sent to the PASS request.
.IP 12
During an active FTP session while waiting for the server to connect back to
curl, the timeout expired.
.IP 13
FTP weird PASV reply, Curl could not parse the reply sent to the PASV request.
.IP 14
FTP weird 227 format. Curl could not parse the 227\-line the server sent.
.IP 15
FTP cannot use host. Could not resolve the host IP we got in the 227\-line.
.IP 16
HTTP/2 error. A problem was detected in the HTTP2 framing layer. This is
somewhat generic and can be one out of several problems, see the error message
for details.
.IP 17
FTP could not set binary. Could not change transfer method to binary.
.IP 18
Partial file. Only a part of the file was transferred.
.IP 19
FTP could not download/access the given file, the RETR (or similar) command
failed.
.IP 21
FTP quote error. A quote command returned error from the server.
.IP 22
HTTP page not retrieved. The requested URL was not found or returned another
error with the HTTP error code being 400 or above. This return code only
appears if \fI\-f, \-\-fail\fP is used.
.IP 23
Write error. Curl could not write data to a local filesystem or similar.
.IP 25
Failed starting the upload. For FTP, the server typically denied the STOR
command.
.IP 26
Read error. Various reading problems.
.IP 27
Out of memory. A memory allocation request failed.
.IP 28
Operation timeout. The specified time\-out period was reached according to the
conditions.
.IP 30
FTP PORT failed. The PORT command failed. Not all FTP servers support the PORT
command, try doing a transfer using PASV instead.
.IP 31
FTP could not use REST. The REST command failed. This command is used for
resumed FTP transfers.
.IP 33
HTTP range error. The range "command" did not work.
.IP 34
HTTP post error. Internal post\-request generation error.
.IP 35
SSL connect error. The SSL handshaking failed.
.IP 36
Bad download resume. Could not continue an earlier aborted download.
.IP 37
FILE could not read file. Failed to open the file. Permissions?
.IP 38
LDAP cannot bind. LDAP bind operation failed.
.IP 39
LDAP search failed.
.IP 41
Function not found. A required LDAP function was not found.
.IP 42
Aborted by callback. An application told curl to abort the operation.
.IP 43
Internal error. A function was called with a bad parameter.
.IP 45
Interface error. A specified outgoing interface could not be used.
.IP 47
Too many redirects. When following redirects, curl hit the maximum amount.
.IP 48
Unknown option specified to libcurl. This indicates that you passed a weird
option to curl that was passed on to libcurl and rejected. Read up in the
manual!
.IP 49
Malformed telnet option.
.IP 52
The server did not reply anything, which here is considered an error.
.IP 53
SSL crypto engine not found.
.IP 54
Cannot set SSL crypto engine as default.
.IP 55
Failed sending network data.
.IP 56
Failure in receiving network data.
.IP 58
Problem with the local certificate.
.IP 59
Could not use specified SSL cipher.
.IP 60
Peer certificate cannot be authenticated with known CA certificates.
.IP 61
Unrecognized transfer encoding.
.IP 63
Maximum file size exceeded.
.IP 64
Requested FTP SSL level failed.
.IP 65
Sending the data requires a rewind that failed.
.IP 66
Failed to initialize SSL Engine.
.IP 67
The username, password, or similar was not accepted and curl failed to log in.
.IP 68
File not found on TFTP server.
.IP 69
Permission problem on TFTP server.
.IP 70
Out of disk space on TFTP server.
.IP 71
Illegal TFTP operation.
.IP 72
Unknown TFTP transfer ID.
.IP 73
File already exists (TFTP).
.IP 74
No such user (TFTP).
.IP 77
Problem reading the SSL CA cert (path? access rights?).
.IP 78
The resource referenced in the URL does not exist.
.IP 79
An unspecified error occurred during the SSH session.
.IP 80
Failed to shut down the SSL connection.
.IP 82
Could not load CRL file, missing or wrong format.
.IP 83
Issuer check failed.
.IP 84
The FTP PRET command failed.
.IP 85
Mismatch of RTSP CSeq numbers.
.IP 86
Mismatch of RTSP Session Identifiers.
.IP 87
Unable to parse FTP file list.
.IP 88
FTP chunk callback reported error.
.IP 89
No connection available, the session is queued.
.IP 90
SSL public key does not matched pinned public key.
.IP 91
Invalid SSL certificate status.
.IP 92
Stream error in HTTP/2 framing layer.
.IP 93
An API function was called from inside a callback.
.IP 94
An authentication function returned an error.
.IP 95
A problem was detected in the HTTP/3 layer. This is somewhat generic and can
be one out of several problems, see the error message for details.
.IP 96
QUIC connection error. This error may be caused by an SSL library error. QUIC
is the protocol used for HTTP/3 transfers.
.IP 97
Proxy handshake error.
.IP 98
A client\-side certificate is required to complete the TLS handshake.
.IP 99
Poll or select returned fatal error.
.IP 100
A value or data field grew larger than allowed.
.IP XX
More error codes might appear here in future releases. The existing ones are
meant to never change.
.SH BUGS
If you experience any problems with curl, submit an issue in the project\(aqs bug
tracker on GitHub: https://github.com/curl/curl/issues
.SH AUTHORS
Daniel Stenberg is the main author, but the whole list of contributors is
found in the separate THANKS file.
.SH WWW
https://curl.se
.SH SEE ALSO
\fBftp (1)\fP, \fBwget (1)\fP