curl

The curl command is used on Linux systems at the terminal. This information was obtained from a Kali Linux distribution using man curl.

You can also run curl from the Windows command line. To see a list of options on Windows, enter curl –help.

As a simple example, you can enter the following command to retrieve the contents of the https://www.ucanbeamillionaire.com page:

curl https://www.ucanbeamillionaire.com/

NAME  

curl – transfer a URL

SYNOPSIS  

curl [options / URLs]

DESCRIPTION

curl is a tool to transfer data from or to a server, using one of the supported protocols (DICT, FILE, FTP, FTPS, GOPHER, HTTP, HTTPS, IMAP, IMAPS, LDAP, LDAPS, MQTT, POP3, POP3S, RTMP, RTMPS, RTSP, SCP, SFTP, SMB, SMBS, SMTP, SMTPS, TELNET and TFTP). The command is designed to work without user interaction.

curl offers a busload of useful tricks like proxy support, user authentication, FTP upload, HTTP post, SSL connections, cookies, file transfer resume, Metalink, and more. As you will see below, the number of features will make your head spin!

curl is powered by libcurl for all transfer-related features.

URL

The URL syntax is protocol-dependent. You’ll find a detailed description in RFC 3986.

You can specify multiple URLs or parts of URLs by writing part sets within braces and quoting the URL as in:

“http://site.{one,two,three}.com”

or you can get sequences of alphanumeric series by using [] as in:

“ftp://ftp.example.com/file[1-100].txt”

“ftp://ftp.example.com/file[001-100].txt” (with leading zeros)

“ftp://ftp.example.com/file[a-z].txt”

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

“http://example.com/archive[1996-1999]/vol[1-4]/part{a,b,c}.html”

You can specify any amount of URLs on the command line. They will be fetched in a sequential manner in the specified order. You can specify command line options and URLs mixed and in any order on the command line.

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

“http://example.com/file[1-100:10].txt”
“http://example.com/file[a-z:2].txt”

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 ‘&’, ‘?’ and ‘*’.

Provide the IPv6 zone index in the URL with an escaped percentage sign and the interface name. Like in

“http://[fe80::3%25eth0]/”

If you specify URL without protocol:// prefix, curl will attempt to guess what protocol you might want. It will then default to HTTP but try other protocols based on often-used host name prefixes. For example, for host names starting with “ftp.” curl will assume you want to speak FTP.

curl will do its best to use what you pass to it as a URL. It is not trying to validate it as a syntactically correct URL by any means but is instead very liberal with what it accepts.

curl will attempt to re-use connections for multiple file transfers, so that getting many files from the same server will not do multiple connects / handshakes. This improves speed. Of course this is only done on files specified on a single command line and cannot be used between separate curl invokes.

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 number of bytes and the speeds are 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 disables 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 (>), -o, –output or similar.

It is not the same case for 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, -#, –progress-bar is your friend. You can also disable the progress meter completely with the -s, –silent option.

OPTIONS

Options start with one or two dashes. Many of the options require an additional value next to them.

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, -d, –data for example, requires a space between it and its value.

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

In general, all boolean options are enabled with —option and yet again disabled with —no-option. That is, you use the exact same option name but prefix it with “no-“. However, in this list we mostly only list and show the –option version of them. (This concept with –no options was added in 7.19.0. Previously most options were toggled on/off on repeated use of the same command line option.)

OptionsPurpose
--abstract-unix-socket (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
argument should not have this leading character.

Added in 7.53.0.
--alt-svc (HTTPS) WARNING: this option is experimental. Do not use
in production.

This option enables the alt-svc parser in curl. If the
file name points to an existing alt-svc cache file, that
will be used. After a completed transfer, the cache will
be saved to the file name again if it has been modified.

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

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

Added in 7.64.1.
--anyauth(HTTP) Tells curl to figure out authentication method by
itself, 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 is used instead of setting
a specific authentication method, which you can do with
--basic, --digest, --ntlm, and --negotiate.

Using --anyauth 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 will
fail.

Used together with -u, --user.

See also --proxy-anyauth, --basic and --digest.
-a, --append(FTP SFTP) When used in an upload, this makes curl append
to the target file instead of overwriting it. If the
remote file doesn't exist, it will be created. Note that
this flag is ignored by some SFTP servers (including
OpenSSH).
--basic(HTTP) Tells curl to use HTTP Basic authentication with
the remote host. This 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 --ntlm, --digest, or --negotiate).

Used together with -u, --user.

See also --proxy-basic.
--cacert (TLS) Tells curl to 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
'CURL_CA_BUNDLE' if it is set, and uses the given path as
a path to a CA cert bundle. This option overrides that
variable.

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

If curl is built against the NSS SSL library, the NSS PEM
PKCS#11 module (libnsspem.so) needs to be available for
this option to work properly.

(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 will use the
certificates in the system and user Keychain to verify the
peer, which is the preferred method of verifying the
peer's certificate chain.

(Schannel only) This option is supported for Schannel in
Windows 7 or later with libcurl 7.60 or later. This option
is supported for backward compatibility with other SSL
engines; instead it is recommended to use Windows' store
of root certificates (the default for Schannel).

If this option is used several times, the last one will be
used.
--capath (TLS) Tells curl to use the specified certificate
directory to verify the peer. Multiple paths can be
provided by separating them with ":" (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 --capath can allow
OpenSSL-powered curl to make SSL-connections much more
efficiently than using --cacert if the --cacert file
contains many CA certificates.

If this option is set, the default capath value will be
ignored, and if it is used several times, the last one
will be used.
--cert-status(TLS) Tells curl to 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 is currently only implemented in the OpenSSL, GnuTLS
and NSS backends.

Added in 7.41.0.
--cert-type (TLS) Tells curl what type the provided client certificate
is using. PEM, DER, ENG and P12 are recognized types. If
not specified, PEM is assumed.

If this option is used several times, the last one will be
used.

See also -E, --cert, --key and --key-type.
-E, --cert (TLS) Tells curl to 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 isn't specified,
it will be queried for on the terminal. Note that this
option assumes a "certificate" file that is the private
key and the client certificate concatenated! See -E,
--cert and --key to specify them independently.

If curl is built against the NSS SSL library then this
option can tell curl the nickname of the certificate to
use within the NSS database defined by the environment
variable SSL_DIR (or by default /etc/pki/nssdb). If the
NSS PEM PKCS#11 module (libnsspem.so) is available then
PEM files may be loaded. If you want to use a file from
the current directory, please precede it with "./" prefix,
in order to avoid confusion with a nickname. If the
nickname contains ":", it needs to be preceded by "\" so
that it is not recognized as password delimiter. If the
nickname contains "\", it needs to be escaped 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:" will be interpreted as a
PKCS#11 URI. If a PKCS#11 URI is provided, then the
--engine option will be set as "pkcs11" if none was
provided and the --cert-type option will be 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 PFX is
not supported; you can import it to a store first). You
can use "\\" to
refer to a certificate in the system certificates store,
for example,
"CurrentUser\MY\934a7ac6f8a5d579285a74fa61e19f23ddfe8d7a".
Thumbprint is usually a SHA-1 hex string which you can see
in certificate details. Following store locations are
supported: CurrentUser, LocalMachine, CurrentService,
Services, CurrentUserGroupPolicy, LocalMachineGroupPolicy,
LocalMachineEnterprise.

If this option is used several times, the last one will be
used.

See also --cert-type, --key and --key-type.
--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 this option is used several times, the last one will be
used.
--compressed-ssh(SCP SFTP) Enables built-in SSH compression. This is a
request, not an order; the server may or may not do it.

Added in 7.56.0.
--compressed(HTTP) Request a compressed response using one of the
algorithms curl supports, and automatically decompress the
content. Headers are not modified.

If this option is used and the server sends an unsupported
encoding, curl will report an error.
-K, --config Specify a text file to read curl arguments from. The
command line arguments found in the text file will be 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 : or
=), the parameter must be enclosed within quotes. 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 column
of a config line is a '#' character, the rest of the line
will be treated as a comment. Only write one option per
physical line in the config file.

Specify the filename to -K, --config as '-' 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 --url option, and not by
simply writing the URL on its own line. So, it could look
similar to this:

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

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

1) Use the CURL_HOME environment variable if set

2) Use the XDG_CONFIG_HOME environment variable if set
(Added in 7.73.0)

3) Use the HOME environment variable if set

4) Non-windows: use getpwuid to find the home directory

5) Windows: use APPDATA if set

6) Windows: use "USERPROFILE0lication Data" if set

7) On windows, if there is no .curlrc file in the home
dir, it checks for one in the same dir the curl executable
is placed. On Unix-like systems, it will simply try to
load .curlrc from the determined home dir.

# --- 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 ---

This option can be used multiple times to load multiple
config files.
--connect-timeout Maximum time in seconds that you allow curl's connection
to take. This only limits the connection phase, so if
curl connects within the given period it will continue -
if not it will exit. Since version 7.32.0, this option
accepts decimal values.

If this option is used several times, the last one will be
used.

See also -m, --max-time.
--connect-to
For a request to the given HOST1:PORT1 pair, connect to
HOST2:PORT2 instead. This option is suitable to direct
requests at a specific server, e.g. at a specific cluster
node in a cluster of servers. This option is only used to
establish the network connection. It does NOT affect the
hostname/port that is used for TLS/SSL (e.g. SNI,
certificate verification) or for the application
protocols. "HOST1" and "PORT1" may be the empty string,
meaning "any host/port". "HOST2" and "PORT2" may also be
the empty string, meaning "use the request's original
host/port".

A "host" 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".

This option can be used many times to add many connect
rules.

See also --resolve and -H, --header. Added in 7.49.0.
-C, --continue-at Continue/Resume a previous file transfer at the given
offset. The given offset is the exact number of bytes that
will be 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 will not be used
by curl.

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

If this option is used several times, the last one will be
used.

See also -r, --range.
-c, --cookie-jar (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. If no cookies are known, no
data will be written. The file will be written using the
Netscape cookie file format. If you set the file name to a
single dash, "-", the cookies will be written to stdout.

This command line option will activate the cookie engine
that makes curl record and use cookies. Another way to
activate it is to use the -b, --cookie option.

If the cookie jar can't be created or written to, the
whole curl operation won't fail or even report an error
clearly. Using -v, --verbose will get a warning displayed,
but that is the only visible feedback you get about this
possibly lethal situation.

If this option is used several times, the last specified
file name will be used.
-b, --cookie (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".

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
will make curl record incoming cookies, which may be handy
if you're using this in combination with the -L,
--location option or do multiple URL transfers on the same
invoke. If the file name is exactly a minus ("-"), curl
will instead read the contents from stdin.

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 -b, --cookie is only used as
input. No cookies will be written to the file. To store
cookies, use the -c, --cookie-jar option.

Exercise caution if you are using this option and multiple
transfers may occur. If you use the NAME1=VALUE1; format,
or in a file use the Set-Cookie format and don't specify a
domain, then the cookie is sent for any domain (even after
redirects are followed) and cannot be modified by a
server-set cookie. If the cookie engine is enabled and a
server sets a cookie of the same name then both will be
sent on a future transfer to that server, likely not what
you intended. To address these issues set a domain in
Set-Cookie (doing that will include sub domains) or use
the Netscape format.

If this option is used several times, the last one will be
used.

Users very often want to both read cookies from a file and
write updated cookies back to a file, so using both -b,
--cookie and -c, --cookie-jar in the same command line is
common.
--create-dirsWhen used in conjunction with the -o, --output option,
curl will create the necessary local directory hierarchy
as needed. This option creates the dirs mentioned with the
-o, --output option, nothing else. If the --output file
name uses no dir or if the dirs it mentions already exist,
no dir will be created.

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

To create remote directories when using FTP or SFTP, try
--ftp-create-dirs.
--create-file-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 'mode' to set on the file at
creation time, instead of the default 0644.

This option takes an octal number as argument.

See also --ftp-create-dirs. Added in 7.75.0.
--crlf(FTP SMTP) Convert LF to CRLF in upload. Useful for MVS
(OS/390).

(SMTP added in 7.40.0)
--crlfile (TLS) Provide a file using PEM format with a Certificate
Revocation List that may specify peer certificates that
are to be considered revoked.

If this option is used several times, the last one will be
used.

Added in 7.19.7.
--curves (TLS) Tells curl to request 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/s_server"
utilities.

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

If this option is set, the default curves list built into
openssl will be ignored.

Added in 7.73.0.
--data-ascii (HTTP) This is just an alias for -d, --data.
--data-binary (HTTP) This posts 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 -d,
--data does, except that newlines and carriage returns are
preserved and conversions are never done.

Like -d, --data 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 will append data as described in -d, --data.
--data-raw (HTTP) This posts data similarly to -d, --data but without
the special interpretation of the @ character.

See also -d, --data. Added in 7.43.0.
--data-urlencode (HTTP) This posts data, similar to the other -d, --data
options with the exception that this performs URL-
encoding.

To be CGI-compliant, the <data> part should begin with a name followed by a separator and a content specification. The <data> part can be passed to curl using one of the following syntaxes:

Data SyntaxesPurpose
contentThis will make curl URL-encode the content and pass
that on. Just be careful so that the content
doesn't contain any = or @ symbols, as that will
then make the syntax match one of the other cases
below!
!ERROR! undefined variable 'content'This will make curl URL-encode the content and pass
that on. The preceding = symbol is not included in
the data.
name=contentThis will make curl URL-encode the content part and
pass that on. Note that the name part is expected
to be URL-encoded already.
@filenameThis will make curl load data from the given file
(including any newlines), URL-encode that data and
pass it on in the POST.
name@filenameThis will make curl 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 name=urlencoded-file-
content. Note that the name is expected to be URL-
encoded already.

See also -d, –data and –data-raw. Added in 7.18.0.

OptionsPurpose
-d, --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 will cause curl to pass the data to the
server using the content-type application/x-www-form-
urlencoded. Compare to -F, --form.

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

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

If you start the data with the letter @, the rest should
be a file name to read the data from, or - if you want
curl to read the data from stdin. Posting data from a file
named 'foobar' would thus be done with -d, --data @foobar.
When -d, --data is told to read from a file like that,
carriage returns and newlines will be stripped out. If you
don't want the @ character to have a special
interpretation use --data-raw instead.

See also --data-binary, --data-urlencode and --data-raw.
This option overrides -F, --form and -I, --head and -T,
--upload-file.
--delegation (GSS/kerberos) Set LEVEL to tell the server what it is
allowed to delegate when it comes to user credentials.

none Don't allow any delegation.

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.

always Unconditionally allow the server to delegate.
--digest(HTTP) Enables HTTP Digest authentication. This is an
authentication scheme that prevents the password from
being sent over the wire in clear text. Use this in
combination with the normal -u, --user option to set user
name and password.

If this option is used several times, only the first one
is used.

See also -u, --user, --proxy-digest and --anyauth. This
option overrides --basic and --ntlm and --negotiate.
--disable-eprt(FTP) Tell curl to disable the use of the EPRT and LPRT
commands when doing active FTP transfers. Curl will
normally always first attempt to use EPRT, then LPRT
before using PORT, but with this option, it will use PORT
right away. EPRT and LPRT are extensions to the original
FTP protocol, and may not work on all servers, but they
enable more functionality in a better way than the
traditional PORT command.

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

If the server is accessed using IPv6, this option will
have 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 -P,
--ftp-port or force it with --ftp-pasv.
--disable-epsv(FTP) (FTP) Tell curl to disable the use of the EPSV
command when doing passive FTP transfers. Curl will
normally always first attempt to use EPSV before PASV, but
with this option, it will not try using EPSV.

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

If the server is an IPv6 host, this option will have 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 -P, --ftp-
port.
-q, --disableIf used as the first parameter on the command line, the
curlrc config file will not be read and used. See the -K,
--config for details on the default config file search
path.
--disallow-username-in-url(HTTP) This tells curl to exit if passed a url containing
a username.

See also --proto. Added in 7.61.0.
--dns-interface (DNS) Tell curl to send outgoing DNS requests through
. This option is a counterpart to --interface
(which does not affect DNS). The supplied string must be
an interface name (not an address).

See also --dns-ipv4-addr and --dns-ipv6-addr. --dns-
interface requires that the underlying libcurl was built
to support c-ares. Added in 7.33.0.
--dns-ipv4-addr
(DNS) Tell curl to bind to when making IPv4
DNS requests, so that the DNS requests originate from this
address. The argument should be a single IPv4 address.

See also --dns-interface and --dns-ipv6-addr. --dns-
ipv4-addr requires that the underlying libcurl was built
to support c-ares. Added in 7.33.0.
--dns-ipv6-addr
(DNS) Tell curl to bind to when making IPv6
DNS requests, so that the DNS requests originate from this
address. The argument should be a single IPv6 address.

See also --dns-interface and --dns-ipv4-addr. --dns-
ipv6-addr requires that the underlying libcurl was built
to support c-ares. Added in 7.33.0.
--dns-servers 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 as : after each IP address.

--dns-servers requires that the underlying libcurl was
built to support c-ares. Added in 7.33.0.
--doh-cert-status(all) Same as --cert-status but used for DOH (DNS-over-
HTTPS).

Added in 7.76.0.
--doh-insecure(all) Same as -k, --insecure but used for DOH (DNS-over-
HTTPS).

Added in 7.76.0.
--doh-url (all) 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 will apply
to DOH since the name lookups take place over SSL.
However, the certificate verification settings are not
inherited and can be controlled separately via --doh-
insecure and --doh-cert-status.

If this option is used several times, the last one will be
used.

Added in 7.62.0.
-D, --dump-header (HTTP FTP) Write the received protocol headers to the
specified file.

This option is handy to use when you want to store the
headers that an HTTP site sends to you. Cookies from the
headers could then be read in a second curl invocation by
using the -b, --cookie option! The -c, --cookie-jar option
is a better way to store cookies.

If no headers are received, the use of this option will
create an empty file.

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

If this option is used several times, the last one will be
used.

See also -o, --output.
--egd-file (TLS) Specify the path name to the Entropy Gathering
Daemon socket. The socket is used to seed the random
engine for SSL connections.

See also --random-file.
--engine (TLS) Select the OpenSSL crypto engine to use for cipher
operations. Use --engine list to print a list of build-
time supported engines. Note that not all (or none) of the
engines may be available at run-time.
--etag-compare (HTTP) This option makes a conditional HTTP request for
the specific ETag read from the given file by sending a
custom If-None-Match header using the extracted ETag.

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

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

COMPARISON: There are 2 types of comparison or ETags: Weak
and Strong. This option expects, and uses a strong
comparison.

Added in 7.68.0.
--etag-save (HTTP) This option saves an HTTP ETag to the specified
file. Etag is usually part of headers returned by a
request. When server sends an ETag, it must be enveloped
by a double quote. This option extracts the ETag without
the double quotes and saves it into the .

A server can send a weak ETag which is prefixed by "W/".
This identifier is not considered, and only relevant ETag
between quotation marks is parsed.

It an ETag wasn't sent by the server or it cannot be
parsed, an empty file is created.

Added in 7.68.0.
--expect100-timeout (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 will
wait one second. This option accepts decimal values! When
curl stops waiting, it will continue as if the response
has been received.

See also --connect-timeout. Added in 7.47.0.
--fail-earlyFail and exit on the first detected transfer error.

When curl is used to do multiple transfers on the command
line, it will attempt to operate on each given URL, one by
one. By default, it will ignore errors if there are more
URLs given and the last URL's success will determine the
error code curl returns. So early failures will be
"hidden" by subsequent successful transfers.

Using this option, curl will instead return 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 is global and does not need to be specified
for each use of -:, --next.

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

Added in 7.52.0.
--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 flag will still allow curl to outputting
and save that content but also to return error 22.

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

See also -f, --fail. Added in 7.76.0.
-f, --fail(HTTP) Fail silently (no output at all) on server errors.
This is mostly done to enable scripts etc to better deal
with failed attempts. 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
flag will prevent curl from outputting that and return
error 22.

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

See also --fail-with-body.
--false-start(TLS) Tells curl to use false start during the TLS
handshake. False start is a mode where a TLS client will
start sending application data before verifying the
server's Finished message, thus saving a round trip when
performing a full handshake.

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

Added in 7.42.0.
--form-string (HTTP SMTP IMAP) Similar to -F, --form 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 -F, --form if there's any possibility that the string
value may accidentally trigger the '@' or '<' features of
-F, --form.

See also -F, --form.
-F, --form (HTTP SMTP IMAP) For HTTP protocol family, this lets curl
emulate a filled-in form in which a user has pressed the
submit button. This causes curl to POST data using the
Content-Type multipart/form-data according to RFC 2388.

For SMTP and IMAP protocols, this is the mean to compose a
multipart mail message to transmit.

This enables uploading of binary files etc. To force the
'content' part to be a file, prefix the file name with an
@ sign. To just get the content part from a file, prefix
the file name 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.

Tell curl to read content from stdin instead of a file by
using - 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's data from a named non-
regular file (such as a named pipe or similar) is
unfortunately not subject to buffering and will be
effectively 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 'profile'
is the name of the form-field to which the file
portrait.jpg will be the input:

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

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

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

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:

curl -F "story=
You can also tell curl what Content-Type to use by using
'type=', in a manner similar to:

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

or

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

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

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

If filename/path contains ',' or ';', it must be quoted by
double-quotes like:

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

or

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

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:

curl -F 'colors="red; green; blue";type=text/x-myapp'
example.com

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

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

or

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

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 '#' 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:

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

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

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 '(', this signals to start a new
multipart: it can be followed by a content type
specification.
- a multipart can be terminated with a '=)' argument.

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

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

Data can be encoded for transfer using encoder=. Available
encodings are binary and 8bit that do nothing else than
adding the corresponding Content-Transfer-Encoding header,
7bit that only rejects 8-bit characters with a transfer
error, quoted-printable and base64 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:

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

See further examples and details in the MANUAL.

This option can be used multiple times.

This option overrides -d, --data and -I, --head and -T,
--upload-file.
--ftp-account (FTP) When an FTP server asks for "account data" after
user name and password has been provided, this data is
sent off using the ACCT command.

If this option is used several times, the last one will be
used.

Added in 7.13.0.
--ftp-alternative-to-user (FTP) If authenticating with the USER and PASS commands
fails, send this command. When connecting to Tumbleweed's
Secure Transport server over FTPS using a client
certificate, using "SITE AUTH" will tell the server to
retrieve the username from the certificate.

Added in 7.15.5.
--ftp-create-dirs(FTP SFTP) When an FTP or SFTP URL/operation uses a path
that doesn't currently exist on the server, the standard
behavior of curl is to fail. Using this option, curl will
instead attempt to create missing directories.

See also --create-dirs.
--ftp-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:

multicwd
curl does a single CWD operation for each path part
in the given URL. For deep hierarchies this means
very many commands. This is how RFC 1738 says it
should be done. This is the default but the slowest
behavior.

nocwd curl does no CWD at all. curl will do SIZE, RETR,
STOR etc and give a full path to the server for all
these commands. This is the fastest behavior.

singlecwd
curl does one CWD with the full target directory
and then operates on the file "normally" (like in
the multicwd case). This is somewhat more standards
compliant than 'nocwd' but without the full penalty
of 'multicwd'.

Added in 7.15.1.

OptionsPurpose
--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 -P, --ftp-port option.

If this option is used several times, only the first one
is used. Undoing an enforced passive really isn't doable
but you must then instead enforce the correct -P, --ftp-
port again.

Passive mode means that curl will try the EPSV command
first and then PASV, unless --disable-epsv is used.

See also --disable-epsv. Added in 7.11.0.
-P, --ftp-port
(FTP) Reverses the default initiator/listener roles when
connecting with FTP. This option makes curl use active
mode. curl then tells the server to connect back to the
client's specified address and port, while passive mode
asks the server to setup an IP address and port for it to
connect to.
should be one of:

interface
e.g. "eth0" to specify which interface's IP address
you want to use (Unix only)

IP address
e.g. "192.168.10.1" to specify the exact IP address

host name
e.g. "my.host.domain" to specify the machine

- make curl pick the same IP address that is already
used for the control connection

If this option is used several times, the last one will be used. Disable the use of PORT with –ftp-pasv. Disable the attempt to use the EPRT command instead of PORT by using –disable-eprt. EPRT is really PORT++.

Since 7.19.5, you can 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.

See also –ftp-pasv and –disable-eprt.

OptionsPurpose
--ftp-pret(FTP) Tell curl to 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.

Added in 7.20.0.
--ftp-skip-pasv-ip(FTP) Tell curl to not use the IP address the server
suggests in its response to curl's PASV command when curl
connects the data connection. Instead curl will re-use the
same IP address it already uses for the control
connection.

Since curl 7.74.0 this option is enabled by default.

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

See also --ftp-pasv. Added in 7.14.2.
--ftp-ssl-ccc-mode (FTP) Sets the CCC mode. The passive mode will not
initiate the shutdown, but instead wait for the server to
do it, and will not reply to the shutdown from the server.
The active mode initiates the shutdown and waits for a
reply from the server.

See also --ftp-ssl-ccc. Added in 7.16.2.
--ftp-ssl-ccc(FTP) Use CCC (Clear Command Channel) Shuts down the
SSL/TLS layer after authenticating. The rest of the
control channel communication will be unencrypted. This
allows NAT routers to follow the FTP transaction. The
default mode is passive.

See also --ssl and --ftp-ssl-ccc-mode. Added in 7.16.1.
--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 doesn't support SSL/TLS.

Added in 7.16.0.
-G, --getWhen used, this option will make all data specified with
-d, --data, --data-binary or --data-urlencode to be used
in an HTTP GET request instead of the POST request that
otherwise would be used. The data will be appended to the
URL with a '?' separator.

If used in combination with -I, --head, the POST data will
instead be appended to the URL with a HEAD request.

If this option is used several times, only the first one
is used. This is because undoing a GET doesn't make sense,
but you should then instead enforce the alternative method
you prefer.
-g, --globoffThis option switches off the "URL globbing parser". When
you set this option, you can specify URLs that contain the
letters {}[] without having them being interpreted by curl
itself. Note that these letters are not normal legal URL
contents but they should be encoded according to the URI
standard.
--happy-eyeballs-timeout-ms Happy eyeballs is an algorithm that attempts to connect to
both IPv4 and IPv6 addresses for dual-stack hosts,
preferring IPv6 first for the 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 this option is used several times, the last one will be
used.

Added in 7.59.0.
--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's
true IP address and port.

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

Added in 7.60.0.
-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.
-H, --header
(HTTP) Extra header to include in the request when sending
HTTP to a server. 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 will be 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're 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 will make sure that each header you add/replace is
sent with the proper end-of-line marker, you should thus
not add that as a part of the header content: do not add
newlines or carriage returns, they will only mess things
up for you.

This option can take an argument in @filename style, which
then adds a header for each line in the input file. Using
@- will make curl read the header file from stdin. Added
in 7.55.0.

You need --proxy-header to send custom headers intended
for a HTTP proxy. Added in 7.37.0.

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

Example:

curl -H "X-First-Name: Joe" http://example.com/

WARNING: headers set with this option will be set in all
requests - even after redirects are followed, like when
told with -L, --location. 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.

This option can be used multiple times to
add/replace/remove multiple headers.

See also -A, --user-agent and -e, --referer.
-h, --help Usage help. This lists all commands of the . If
no arg was provided, curl will display the most important
command line arguments. If the argument "all" was
provided, curl will display all options available. If the
argument "category" was provided, curl will display all
categories and their meanings.
--hostpubmd5 (SFTP SCP) Pass a string containing 32 hexadecimal digits.
The string should be the 128 bit MD5 checksum of the
remote host's public key, curl will refuse the connection
with the host unless the md5sums match.

Added in 7.17.1.
--http0.9(HTTP) Tells curl to be fine with HTTP version 0.9
response.

HTTP/0.9 is a completely headerless response and therefore
you can also connect with this to non-HTTP servers and
still get a response since curl will simply transparently
downgrade - if allowed.

Since curl 7.66.0, HTTP/0.9 is disabled by default.
-0, --http1.0(HTTP) Tells curl to use HTTP version 1.0 instead of using
its internally preferred HTTP version.

This option overrides --http1.1 and --http2.
--http1.1(HTTP) Tells curl to use HTTP version 1.1.

This option overrides -0, --http1.0 and --http2. Added in
7.33.0.
--http2-prior-knowledge(HTTP) Tells curl to issue its non-TLS HTTP requests using
HTTP/2 without HTTP/1.1 Upgrade. It requires prior
knowledge that the server supports HTTP/2 straight away.
HTTPS requests will still do HTTP/2 the standard way with
negotiated protocol version in the TLS handshake.

--http2-prior-knowledge requires that the underlying
libcurl was built to support HTTP/2. This option overrides
--http1.1 and -0, --http1.0 and --http2. Added in 7.49.0.
--http2(HTTP) Tells curl to use HTTP version 2.

See also --http1.1 and --http3. --http2 requires that the
underlying libcurl was built to support HTTP/2. This
option overrides --http1.1 and -0, --http1.0 and
--http2-prior-knowledge. Added in 7.33.0.
--http3(HTTP) WARNING: this option is experimental. Do not use in
production.

Tells curl to use HTTP version 3 directly to the host and
port number used in the URL. A normal HTTP/3 transaction
will be done to a host and then get redirected via Alt-
SVc, but this option allows a user to circumvent that when
you know that the target speaks HTTP/3 on the given host
and port.

This option will make curl fail if a QUIC connection
cannot be established, it cannot fall back to a lower HTTP
version on its own.

See also --http1.1 and --http2. --http3 requires that the
underlying libcurl was built to support HTTP/3. This
option overrides --http1.1 and -0, --http1.0 and --http2
and --http2-prior-knowledge. Added in 7.66.0.
--ignore-content-length(FTP HTTP) For HTTP, Ignore the Content-Length header.
This is particularly useful for servers running Apache
1.x, which will report incorrect Content-Length for files
larger than 2 gigabytes.

For FTP (since 7.46.0), skip the RETR command to figure
out the size before downloading a file.
-i, --includeInclude the HTTP response headers in the output. The HTTP
response headers can include things like server name,
cookies, date of the document, HTTP version and more...

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

See also -v, --verbose.
-k, --insecure(TLS) By default, every SSL connection curl makes is
verified to be secure. This option allows curl to proceed
and operate even for server connections otherwise
considered insecure.

The server connection is verified by making sure the
server's certificate contains the right name and verifies
successfully using the cert store.

See this online resource for further details:
https://curl.se/docs/sslcerts.html

See also --proxy-insecure and --cacert.
--interface Perform an operation using a specified interface. You can
enter interface name, IP address or host name. An example
could look like:

curl --interface eth0:1 https://www.example.com/

If this option is used several times, the last one will be
used.

On Linux it can be used to specify a VRF, but the binary
needs to either have CAP_NET_RAW or to be run as root.
More information about Linux VRF:
https://www.kernel.org/doc/Documentation/networking/vrf.txt

See also --dns-interface.
-4, --ipv4This option tells curl to resolve names to IPv4 addresses
only, and not for example try IPv6.

See also --http1.1 and --http2. This option overrides -6,
--ipv6.
-6, --ipv6This option tells curl to resolve names to IPv6 addresses
only, and not for example try IPv4.

See also --http1.1 and --http2. This option overrides -4,
--ipv4.
-j, --junk-session-cookies (HTTP) When curl is told to read cookies from a given
file, this option will make it discard all "session
cookies". This will basically have the same effect as if a
new session is started. Typical browsers always discard
session cookies when they're closed down.

See also -b, --cookie and -c, --cookie-jar.
--keepalive-time This option sets 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, recent AIX,
HP-UX and more). This option has no effect if --no-
keepalive is used.

If this option is used several times, the last one will be
used. If unspecified, the option defaults to 60 seconds.

Added in 7.18.0.
--key-type (TLS) Private key file type. Specify which type your --key
provided private key is. DER, PEM, and ENG are supported.
If not specified, PEM is assumed.

If this option is used several times, the last one will be
used.
--key (TLS SSH) Private key file name. 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:" will be interpreted as a
PKCS#11 URI. If a PKCS#11 URI is provided, then the
--engine option will be set as "pkcs11" if none was
provided and the --key-type option will be set as "ENG" if
none was provided.

If this option is used several times, the last one will be
used.
--krb (FTP) Enable Kerberos authentication and use. The level
must be entered and should be one of 'clear', 'safe',
'confidential', or 'private'. Should you use a level that
is not one of these, 'private' will instead be used.

If this option is used several times, the last one will be
used.

--krb requires that the underlying libcurl was built to
support Kerberos.
--libcurl Append this option to any ordinary curl command line, and
you will get a libcurl-using C source code written to the
file that does the equivalent of what your command-line
operation does!

If this option is used several times, the last given file
name will be used.

Added in 7.16.1.
--limit-rate 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'd 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 'k' or 'K' will count the
number as kilobytes, 'm' or 'M' makes it megabytes, while
'g' or 'G' makes it gigabytes. Examples: 200K, 3m and 1G.

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

If this option is used several times, the last one will be
used.
-l, --list-only(FTP POP3) (FTP) When listing an FTP directory, this
switch forces a name-only view. This is especially useful
if the user wants to machine-parse the contents of an FTP
directory since the normal directory view doesn't use a
standard look or format. When used like this, the option
causes a 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.

(POP3) 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.

Note: When combined with -X, --request, this option can be
used to send an UIDL command instead, so the user may use
the email's unique identifier rather than it's message id
to make the request.

Added in 4.0.
--local-port 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 that will be busy
at times so setting this range to something too narrow
might cause unnecessary connection setup failures.

Added in 7.15.2.
--location-trusted(HTTP) Like -L, --location, but will allow 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'll send your
authentication info (which is plaintext in the case of
HTTP Basic authentication).

See also -u, --user.
-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 will make
curl redo the request on the new place. If used together
with -i, --include or -I, --head, headers from all
requested pages will be shown. When authentication is
used, curl only sends its credentials to the initial host.
If a redirect takes curl to a different host, it won't be
able to intercept the user+password. See also --location-
trusted on how to change this. You can limit the amount of
redirects to follow by using the --max-redirs option.

When curl follows a redirect and if the request is a POST,
it will do 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 will re-send 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:
--post301, --post302 and --post303.

The method set with -X, --request overrides the method
curl would otherwise select to use.
--login-options (IMAP POP3 SMTP) Specify the login options to use during
server authentication.

You can use the 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 the login options please see RFC 2384,
RFC 5092 and IETF draft draft-earhart-url-smtp-00.txt

If this option is used several times, the last one will be
used.

Added in 7.34.0.
--mail-auth
(SMTP) Specify a single address. This will be used to
specify the authentication address (identity) of a
submitted message that is being relayed to another server.

See also --mail-rcpt and --mail-from. Added in 7.25.0.
--mail-from
(SMTP) Specify a single address that the given mail should
get sent from.

See also --mail-rcpt and --mail-auth. Added in 7.20.0.
--mail-rcpt
(SMTP) Specify a single address, user name or mailing list
name. Repeat this option several times to send to multiple
recipients.

When performing a mail transfer, the recipient should
specify a valid email address to send the mail to.

When performing an address verification (VRFY command),
the recipient should be specified as the user name or user
name and domain (as per Section 3.5 of RFC5321). (Added in
7.34.0)

When performing a mailing list expand (EXPN command), the
recipient should be specified using the mailing list name,
such as "Friends" or "London-Office". (Added in 7.34.0)

Added in 7.20.0.
-M, --manual Manual. Display the huge help text.
--max-filesize Specify the maximum size (in bytes) of a file to download.
If the file requested is larger than this value, the
transfer will not start and curl will return with exit
code 63.

A size modifier may be used. For example, Appending 'k' or
'K' will count the number as kilobytes, 'm' or 'M' makes
it megabytes, while 'g' or 'G' makes it gigabytes.
Examples: 200K, 3m and 1G. (Added in 7.58.0)

NOTE: The file size is not always known prior to download,
and for such files this option has no effect even if the
file transfer ends up being larger than this given limit.
This concerns both FTP and HTTP transfers.

See also --limit-rate.
--max-redirs (HTTP) Set maximum number of redirection-followings
allowed. When -L, --location is used, is used to prevent
curl from following redirections too much. By default, the
limit is set to 50 redirections. Set this option to -1 to
make it unlimited.

If this option is used several times, the last one will be
used.
-m, --max-time Maximum time in seconds that you allow the whole operation
to take. This is useful for preventing your batch jobs
from hanging for hours due to slow networks or links going
down. Since 7.32.0, this option accepts decimal values,
but the actual timeout will decrease in accuracy as the
specified timeout increases in decimal precision.

If this option is used several times, the last one will be
used.

See also --connect-timeout.
--metalinkThis option can tell curl to parse and process a given URI
as Metalink file (both version 3 and 4 (RFC 5854) are
supported) and make use of the mirrors listed within for
failover if there are errors (such as the file or server
not being available). It will also verify the hash of the
file after the download completes. The Metalink file
itself is downloaded and processed in memory and not
stored in the local file system.

Example to use a remote Metalink file:

curl --metalink http://www.example.com/example.metalink

To use a Metalink file in the local file system, use FILE
protocol (file://):

curl --metalink file:///example.metalink

Please note that if FILE protocol is disabled, there is no
way to use a local Metalink file at the time of this
writing. Also note that if --metalink and -i, --include
are used together, --include will be ignored. This is
because including headers in the response will break
Metalink parser and if the headers are included in the
file described in Metalink file, hash check will fail.

--metalink requires that the underlying libcurl was built
to support metalink. Added in 7.27.0.
--negotiate(HTTP) Enables Negotiate (SPNEGO) authentication.

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

When using this option, you must also provide a fake -u,
--user option to activate the authentication code
properly. Sending a '-u :' is enough as the user name and
password from the -u, --user option aren't actually used.

If this option is used several times, only the first one
is used.

See also --basic, --ntlm, --anyauth and --proxy-negotiate.
--netrc-file This option is similar to -n, --netrc, except that you
provide the path (absolute or relative) to the netrc file
that curl should use. You can only specify one netrc file
per invocation. If several --netrc-file options are
provided, the last one will be used.

It will abide by --netrc-optional if specified.

This option overrides -n, --netrc. Added in 7.21.5.
--netrc-optionalVery similar to -n, --netrc, but this option makes the
.netrc usage optional and not mandatory as the -n, --netrc
option does.

See also --netrc-file. This option overrides -n, --netrc.
-n, --netrc Makes curl scan the .netrc (_netrc on Windows) file in the
user's home directory for login name and password. This is
typically used for FTP on Unix. If used with HTTP, curl
will enable user authentication. See netrc(5) ftp(1) for
details on the file format. Curl will not complain if that
file doesn't have the right permissions (it should not be
either world- or group-readable). The environment variable
"HOME" is used to find the home directory.

A quick and very simple example of how to setup a .netrc
to allow curl to FTP to the machine host.domain.com with
user name 'myself' and password 'secret' should look
similar to:

machine host.domain.com login myself password secret
-:, --nextTells curl to 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 user names or
custom requests for each.

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

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

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

Added in 7.36.0.
--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.

See also --no-npn and --http2. --no-alpn requires that the
underlying libcurl was built to support TLS. Added in
7.36.0.
-N, --no-bufferDisables the buffering of the output stream. In normal
work situations, curl will use a standard buffered output
stream that will have the effect that it will output the
data in chunks, not necessarily exactly when the data
arrives. Using this option will disable that buffering.

Note that this is the negated option name documented. You
can thus use --buffer to enforce the buffering.
--no-keepaliveDisables 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 --keepalive to enforce keepalive.
--no-npn(HTTPS) 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.

See also --no-alpn and --http2. --no-npn requires that the
underlying libcurl was built to support TLS. Added in
7.36.0.
--no-progress-meterOption to switch off the progress meter output without
muting or otherwise affecting warning and informational
messages like -s, --silent does.

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

See also -v, --verbose and -s, --silent. Added in 7.67.0.
--no-sessionid(TLS) Disable curl's 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 --sessionid to enforce session-ID caching.

Added in 7.16.0.
--noproxy Comma-separated list of hosts which do not 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.

Since 7.53.0, This option overrides the environment
variables that disable the proxy. If there's an
environment variable disabling a proxy, you can set
noproxy list to "" to override it.

Added in 7.19.4.
--ntlm-wb(HTTP) Enables NTLM much in the style --ntlm does, but
hand over the authentication to the separate binary
ntlmauth application that is executed when needed.

See also --ntlm and --proxy-ntlm.
--ntlm(HTTP) Enables 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 --proxy-ntlm.

If this option is used several times, only the first one
is used.

See also --proxy-ntlm. --ntlm requires that the underlying
libcurl was built to support TLS. This option overrides
--basic and --negotiate and --digest and --anyauth.
--oauth2-bearer (IMAP POP3 SMTP HTTP) Specify the Bearer Token for OAUTH
2.0 server authentication. The Bearer Token is used in
conjunction with the user name which can be specified as
part of the --url or -u, --user options.

The Bearer Token and user name are formatted according to
RFC 6750.

If this option is used several times, the last one will be
used.
-o, --output Write output to instead of stdout. If you are using
{} or [] to fetch multiple documents, you should quote the
URL and you can use '#' followed by a number in the
specifier. That variable will be replaced with the current
string for the URL being fetched. Like in:

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

or use several variables like:

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

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:

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

and the order of the -o options and the URLs doesn't
matter, just that the first -o is for the first URL and so
on, so the above command line can also be written as

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

See also the --create-dirs option to create the local
directories dynamically. Specifying the output as '-' (a
single dash) will force the output to be done to stdout.

See also -O, --remote-name, --remote-name-all and -J,
--remote-header-name.
--parallel-maxWhen asked to do parallel transfers, using -Z, --parallel,
this option controls the maximum amount of transfers to do
simultaneously.

The default is 50.

See also -Z, --parallel. Added in 7.66.0.
-Z, --parallelMakes curl perform its transfers in parallel as compared
to the regular serial manner.

Added in 7.66.0.
--pass (SSH TLS) Passphrase for the private key

If this option is used several times, the last one will be
used.
--path-as-is Tell curl to not handle sequences of /../ or /./ in the
given URL path. Normally curl will squash or merge them
according to standards but with this option set you tell
it not to do that.

Added in 7.42.0.
--pinnedpubkey (TLS) Tells curl to 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
´sha256//´ and separated by ´;´

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 will
abort the connection before sending or receiving any data.

PEM/DER support:
7.39.0: OpenSSL, GnuTLS and GSKit
7.43.0: NSS and wolfSSL
7.47.0: mbedtls sha256 support:
7.44.0: OpenSSL, GnuTLS, NSS and wolfSSL
7.47.0: mbedtls Other SSL backends not supported.

If this option is used several times, the last one will be
used.
--post301(HTTP) Tells curl to respect RFC 7231/6.4.2 and not
convert POST requests into GET requests when following a
301 redirection. 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 -L, --location.

See also --post302, --post303 and -L, --location. Added in
7.17.1.
--post302(HTTP) Tells curl to respect RFC 7231/6.4.3 and not
convert POST requests into GET requests when following a
302 redirection. 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 -L, --location.

See also --post301, --post303 and -L, --location. Added in
7.19.1.
--post303(HTTP) Tells curl to violate RFC 7231/6.4.4 and not
convert POST requests into GET requests when following 303
redirections. A server may require a POST to remain a POST
after a 303 redirection. This option is meaningful only
when using -L, --location.

See also --post302, --post301 and -L, --location. Added in
7.26.0.
--preproxy [protocol://]host[:port]Use the specified SOCKS proxy before connecting to an HTTP
or HTTPS -x, --proxy. 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 will make 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 this option is used several times, the last one will be
used.

Added in 7.52.0.
-#, --progress-barMake curl display transfer progress as a simple progress
bar instead of the standard, more informational, meter.

This progress bar draws a single line of '#' characters
across the screen and shows a percentage if the transfer
size is known. For transfers without a known size, there
will be 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.
--proto-default Tells curl to use protocol for any URL missing a scheme
name.

Example:

curl --proto-default https ftp.mozilla.org

An unknown or unsupported protocol causes error
CURLE_UNSUPPORTED_PROTOCOL (1).

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

Without this option curl would make a guess based on the
host, see --url for details.

Added in 7.45.0.
--proto-redir Tells curl to limit what protocols it may use on redirect.
Protocols denied by --proto are not overridden by this
option. See --proto for how protocols are represented.

Example, allow only HTTP and HTTPS on redirect:

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

By default curl will allow HTTP, HTTPS, FTP and FTPS on
redirect (7.65.2). Older versions of curl allowed all
protocols on redirect except several disabled for security
reasons: Since 7.19.4 FILE and SCP are disabled, and since
7.40.0 SMB and SMBS are also disabled. Specifying all or
+all enables all protocols on redirect, including those
disabled for security.

Added in 7.20.2.
--proto Tells curl to limit what protocols it may use in the
transfer. Protocols are evaluated left to right, are comma
separated, and are each a protocol name or 'all',
optionally prefixed by zero or more modifiers. Available
modifiers are:

+ Permit this protocol in addition to protocols already
permitted (this is the default if no modifier is used).

- Deny this protocol, removing it from the list of
protocols already permitted.

= Permit only this protocol (ignoring the list already
permitted), though subject to later modification by
subsequent entries in the comma separated list.

For example:

--proto -ftps
uses the default protocols, but disables ftps

--proto -all,https,+http
only enables http and https

--proto =http,https
also only enables http and https

Unknown 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.

See also –proto-redir and –proto-default. Added in 7.20.2.

OptionsPurpose
--proxy-anyauthTells curl to pick a suitable authentication method when
communicating with the given HTTP proxy. This might cause
an extra request/response round-trip.

See also -x, --proxy, --proxy-basic and --proxy-digest.
Added in 7.13.2.
--proxy-basicTells curl to use HTTP Basic authentication when
communicating with the given proxy. Use --basic for
enabling HTTP Basic with a remote host. Basic is the
default authentication method curl uses with proxies.

See also -x, --proxy, --proxy-anyauth and --proxy-digest.
--proxy-cacert Same as --cacert but used in HTTPS proxy context.

See also --proxy-capath, --cacert, --capath and -x,
--proxy. Added in 7.52.0.
--proxy-capath Same as --capath but used in HTTPS proxy context.

See also --proxy-cacert, -x, --proxy and --capath. Added
in 7.52.0.
--proxy-cert-type Same as --cert-type but used in HTTPS proxy context.

Added in 7.52.0.
--proxy-cert Same as -E, --cert but used in HTTPS proxy context.

Added in 7.52.0.
--proxy-ciphers Same as --ciphers but used in HTTPS proxy context.

Added in 7.52.0.
--proxy-crlfile Same as --crlfile but used in HTTPS proxy context.

Added in 7.52.0.
--proxy-digestTells curl to use HTTP Digest authentication when
communicating with the given proxy. Use --digest for
enabling HTTP Digest with a remote host.

See also -x, --proxy, --proxy-anyauth and --proxy-basic.
--proxy-header
(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 -H, --header 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 will make sure that each header you add/replace is
sent with the proper end-of-line marker, you should thus
not add that as a part of the header content: do not add
newlines or carriage returns, they will only mess things
up for you.

Headers specified with this option will not be included in
requests that curl knows will not be sent to a proxy.

Starting in 7.55.0, this option can take an argument in
@filename style, which then adds a header for each line in
the input file. Using @- will make curl read the header
file from stdin.

This option can be used multiple times to
add/replace/remove multiple headers.

Added in 7.37.0.
--proxy-insecureSame as -k, --insecure but used in HTTPS proxy context.

Added in 7.52.0.
--proxy-key-type Same as --key-type but used in HTTPS proxy context.

Added in 7.52.0.
--proxy-key Same as --key but used in HTTPS proxy context.
--proxy-negotiateTells curl to use HTTP Negotiate (SPNEGO) authentication
when communicating with the given proxy. Use --negotiate
for enabling HTTP Negotiate (SPNEGO) with a remote host.

See also --proxy-anyauth and --proxy-basic. Added in
7.17.1.
--proxy-ntlmTells curl to use HTTP NTLM authentication when
communicating with the given proxy. Use --ntlm for
enabling NTLM with a remote host.

See also --proxy-negotiate and --proxy-anyauth.
--proxy-pass Same as --pass but used in HTTPS proxy context.

Added in 7.52.0.
--proxy-pinnedpubkey (TLS) Tells curl to 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
´sha256//´ and separated by ´;´

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 will
abort the connection before sending or receiving any data.

If this option is used several times, the last one will be
used.
--proxy-service-name This option allows you to change the service name for
proxy negotiation.

Added in 7.43.0.
--proxy-ssl-allow-beastSame as --ssl-allow-beast but used in HTTPS proxy context.

Added in 7.52.0.
--proxy-tls13-ciphers (TLS) Specifies 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 --proxy-ciphers option.

If this option is used several times, the last one will be
used.
--proxy-tlsauthtype Same as --tlsauthtype but used in HTTPS proxy context.

Added in 7.52.0.
--proxy-tlspassword Same as --tlspassword but used in HTTPS proxy context.

Added in 7.52.0.
--proxy-tlsuser Same as --tlsuser but used in HTTPS proxy context.

Added in 7.52.0.
--proxy-tlsv1Same as -1, --tlsv1 but used in HTTPS proxy context.

Added in 7.52.0.
-U, --proxy-user Specify the user name 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 user name and password from your
environment by specifying a single colon with this option:
"-U :".

On systems where it works, curl will hide 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 will still be visible for
a brief 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 this option is used several times, the last one will be
used.
-x, --proxy [protocol://]host[:port]Use the specified proxy.

The proxy string can be specified with a protocol://
prefix. No protocol specified or http:// will be treated
as HTTP proxy. Use socks4://, socks4a://, socks5:// or
socks5h:// to request a specific SOCKS version to be used.
(The protocol support was added in curl 7.21.7)

HTTPS proxy support via https:// protocol prefix was added
in 7.52.0 for OpenSSL, GnuTLS and NSS.

Unrecognized and unsupported proxy protocols cause an
error since 7.52.0. Prior versions may ignore the
protocol and use 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's an environment variable
setting a proxy, you can set proxy to "" to override it.

All operations that are performed over an HTTP proxy will
transparently be 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 -p, --proxytunnel 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 exact same way as the
proxy environment variables, including the protocol prefix
(http://) and the embedded user + password.

If this option is used several times, the last one will be
used.
--proxy1.0 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
-x, --proxy, is that attempts to use CONNECT through the
proxy will specify an HTTP 1.0 protocol instead of the
default HTTP 1.1.
-p, --proxytunnelWhen an HTTP proxy is used -x, --proxy, this option will
make curl tunnel 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 --suppress-connect-headers.

See also -x, --proxy.
--pubkey (SFTP SCP) Public key file name. Allows you to provide
your public key in this separate file.

If this option is used several times, the last one will be
used.

(As of 7.39.0, 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.)
-Q, --quote(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 PWD command in an FTP
transfer, to be exact). To make commands take place after
a successful transfer, prefix them with a dash '-'. To
make commands be sent after curl has changed the working
directory, just before the transfer command(s), prefix the
command with a '+' (this is only supported for FTP). You
may specify any number of commands.

If the server returns failure for one of the commands, the
entire operation will be 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.

Prefix the command with an asterisk (*) to make curl
continue even if the command fails as by default curl will
stop at first failure.

This option can be used multiple times.

SFTP is a binary protocol. Unlike for FTP, curl interprets
SFTP quote commands itself before sending them to the
server. File names may be quoted shell-style to embed
spaces or special characters. Following is the list of
all supported SFTP quote commands:

atime date file
The atime command sets the last access time of the
file named by the file operand. The expression> can be all sorts of date strings, see
the curl_getdate(3) man page for date expression
details. (Added in 7.73.0)

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.

chmod mode file
The chmod command modifies the file mode bits of
the specified file. The mode operand is an octal
integer mode number.

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.

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.

mkdir directory_name
The mkdir command creates the directory named by
the directory_name operand.

mtime date file
The mtime command sets the last modification time
of the file named by the file operand. The expression> can be all sorts of date strings, see
the curl_getdate(3) man page for date expression
details. (Added in 7.73.0)

pwd The pwd command returns the absolute pathname of
the current working directory.

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.

rm file
The rm command removes the file specified by the
file operand.

rmdir directory
The rmdir command removes the directory entry
specified by the directory operand, provided it is
empty.

symlink source_file target_file
See ln.
--random-file Specify the path name to file containing what will be
considered as random data. The data may be used to seed
the random engine for SSL connections. See also the
--egd-file option.
-r, --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.

0-499 specifies the first 500 bytes

500-999
specifies the second 500 bytes

-500 specifies the last 500 bytes

9500- specifies the bytes from offset 9500 and forward

0-0,-1 specifies the first and last byte only(*)(HTTP)

100-199,500-599
specifies two separate 100-byte ranges(*) (HTTP)

(*) = NOTE that this will cause the server to reply with a
multipart response, which will be 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 'start' and
'stop' fields of the 'start-stop' range syntax. If a non-
digit character is given in the range, the server's
response will be unspecified, depending on the server's
configuration.

You should also be aware that many HTTP/1.1 servers do not
have this feature enabled, so that when you attempt to get
a range, you'll instead get the whole document.

FTP and SFTP range downloads only support the simple
'start-stop' syntax (optionally with one of the numbers
omitted). FTP use depends on the extended FTP command
SIZE.

If this option is used several times, the last one will be
used.
--raw(HTTP) When used, it disables all internal HTTP decoding
of content or transfer encodings and instead makes them
passed on unaltered, raw.

Added in 7.16.2.
-e, --referer (HTTP) Sends the "Referrer Page" information to the HTTP
server. This can also be set with the -H, --header flag of
course. When used with -L, --location you can append
";auto" to the -e, --referer 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 don't set an initial -e, --referer.

If this option is used several times, the last one will be
used.

See also -A, --user-agent and -H, --header.
-J, --remote-header-name(HTTP) This option tells the -O, --remote-name option to
use the server-specified Content-Disposition filename
instead of extracting a filename from the URL.

If the server specifies a file name and a file with that
name already exists in the current working directory it
will not be overwritten and an error will occur. If the
server doesn't specify a file name then this option has no
effect.

There's no attempt to decode %-sequences (yet) in the
provided file name, so this option may provide you with
rather unexpected file names.

WARNING: 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 possibly be loaded
automatically by Windows or some third party software.
--remote-name-allThis option changes the default action for all given URLs
to be dealt with as if -O, --remote-name were used for
each one. So if you want to disable that for a specific
URL after --remote-name-all has been used, you must use
"-o -" or --no-remote-name.

Added in 7.19.0.
-O, --remote-nameWrite 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 will be 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.

The remote file name to use for saving is extracted from
the given URL, nothing else, and if it already exists it
will be overwritten. If you want the server to be able to
choose the file name refer to -J, --remote-header-name
which can be used in addition to this option. If the
server chooses a file name and that name already exists it
will not be overwritten.

There is no URL decoding done on the file name. If it has
%20 or other URL encoded parts of the name, they will end
up as-is as file name.

You may use this option as many times as the number of
URLs you have.
-R, --remote-timeWhen used, this will make curl attempt to figure out the
timestamp of the remote file, and if that is available
make the local file get that same timestamp.
--request-target(HTTP) Tells curl to 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 doesn't follow
the regular URL pattern, like "OPTIONS *".

Added in 7.55.0.
-X, --request (HTTP) Specifies a custom request method to use when
communicating with the HTTP server. The specified request
method will be used instead of the method otherwise used
(which defaults to GET). Read the HTTP 1.1 specification
for details and explanations. Common additional HTTP
requests include PUT and DELETE, but related technologies
like WebDAV offers PROPFIND, COPY, MOVE and more.

Normally you don't need this option. All sorts of GET,
HEAD, POST and PUT 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. So for
example if you want to make a proper HEAD request, using
-X HEAD will not suffice. You need to use the -I, --head
option.

The method string you set with -X, --request will be used
for all requests, which if you for example use -L,
--location may cause unintended side-effects when curl
doesn't change request method according to the HTTP 30x
response codes - and similar.

(FTP) Specifies a custom FTP command to use instead of
LIST when doing file lists with FTP.

(POP3) Specifies a custom POP3 command to use instead of
LIST or RETR. (Added in 7.26.0)

(IMAP) Specifies a custom IMAP command to use instead of
LIST. (Added in 7.30.0)

(SMTP) Specifies a custom SMTP command to use instead of
HELP or VRFY. (Added in 7.34.0)

If this option is used several times, the last one will be
used.
--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 will be 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 --resolve with a specific
host and port will be used first.

The provided address set by this option will be used even
if -4, --ipv4 or -6, --ipv6 is set to make curl use
another IP version.

By prefixing the host with a '+' you can make the entry
time out after curl's default timeout (1 minute). Note
that this will only make sense for long running parallel
transfers with a lot of files. In such cases, if this
option is used curl will try to resolve the host as it
normally would once the timeout has expired.

Support for providing the IP address within [brackets] was
added in 7.57.0.

Support for providing multiple IP addresses per entry was
added in 7.59.0.

Support for resolving with wildcard was added in 7.64.0.

Support for the '+' prefix was was added in 7.75.0.

This option can be used many times to add many host names
to resolve.

Added in 7.21.3.
--retry-connrefusedIn addition to the other conditions, consider ECONNREFUSED
as a transient error too for --retry. This option is used
together with --retry.

Added in 7.52.0.
--retry-delay 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 --retry is also used.
Setting this delay to zero will make curl use the default
backoff time.

If this option is used several times, the last one will be
used.

Added in 7.12.3.
--retry-max-time The retry timer is reset before the first transfer
attempt. Retries will be done as usual (see --retry) as
long as the timer hasn't reached this given limit. Notice
that if the timer hasn't reached the limit, the request
will be made and while performing, it may take longer than
this given time period. To limit a single request´s
maximum time, use -m, --max-time. Set this option to zero
to not timeout retries.

If this option is used several times, the last one will be
used.

Added in 7.12.3.
--retry If a transient error is returned when curl tries to
perform a transfer, it will retry 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 will first wait
one second and then for all forthcoming retries it will
double the waiting time until it reaches 10 minutes which
then will be the delay between the rest of the retries.
By using --retry-delay you disable this exponential
backoff algorithm. See also --retry-max-time to limit the
total time allowed for retries.

Since curl 7.66.0, curl will comply with the Retry-After:
response header if one was present to know when to issue
the next retry.

If this option is used several times, the last one will be
used.

Added in 7.12.3.
--sasl-authzid Use this authorisation identity (authzid), during SASL
PLAIN authentication, in addition to the authentication
identity (authcid) as specified by -u, --user.

If the option isn't specified, the server will derive the
authzid from the authcid, but if specified, and depending
on the server implementation, it may be used to access
another user's inbox, that the user has been granted
access to, or a shared mailbox for example.

Added in 7.66.0.
--sasl-irEnable initial response in SASL authentication.

Added in 7.31.0.
--service-name This option allows you to change the service name for
SPNEGO.

Examples: --negotiate --service-name sockd would use
sockd/server-name.

Added in 7.43.0.
-S, --show-errorWhen used with -s, --silent, it makes curl show an error
message if it fails.

See also --no-progress-meter.
-s, --silentSilent or quiet mode. Don't show progress meter or error
messages. Makes Curl mute. It will still output the data
you ask for, potentially even to the terminal/stdout
unless you redirect it.

Use -S, --show-error in addition to this option to disable
progress meter but still show error messages.

See also -v, --verbose, --stderr and --no-progress-meter.
--socks4 Use the specified SOCKS4 proxy. If the port number is not
specified, it is assumed at port 1080.

This option overrides any previous use of -x, --proxy, as
they are mutually exclusive.

Since 7.21.7, this option is superfluous since you can
specify a socks4 proxy with -x, --proxy using a socks4://
protocol prefix.

Since 7.52.0, --preproxy can be used to specify a SOCKS
proxy at the same time -x, --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 this option is used several times, the last one will be
used.

Added in 7.15.2.
--socks4a Use the specified SOCKS4a proxy. If the port number is not
specified, it is assumed at port 1080.

This option overrides any previous use of -x, --proxy, as
they are mutually exclusive.

Since 7.21.7, this option is superfluous since you can
specify a socks4a proxy with -x, --proxy using a
socks4a:// protocol prefix.

Since 7.52.0, --preproxy can be used to specify a SOCKS
proxy at the same time -x, --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 this option is used several times, the last one will be
used.

Added in 7.18.0.
--socks5-basicTells curl to use username/password authentication when
connecting to a SOCKS5 proxy. The username/password
authentication is enabled by default. Use --socks5-gssapi
to force GSS-API authentication to SOCKS5 proxies.

Added in 7.55.0.
--socks5-gssapi-necAs 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 --socks5-gssapi-nec allows the unprotected
exchange of the protection mode negotiation.

Added in 7.19.4.
--socks5-gssapi-service The default service name for a socks server is
rcmd/server-fqdn. This option allows you to change it.

Examples: --socks5 proxy-name --socks5-gssapi-service
sockd would use sockd/proxy-name --socks5 proxy-name
--socks5-gssapi-service sockd/real-name would use
sockd/real-name for cases where the proxy-name does not
match the principal name.

Added in 7.19.4.
--socks5-gssapiTells curl to 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 --socks5-basic to force username/password
authentication to SOCKS5 proxies.

Added in 7.55.0.
--socks5-hostname Use the specified SOCKS5 proxy (and let the proxy resolve
the host name). If the port number is not specified, it is
assumed at port 1080.

This option overrides any previous use of -x, --proxy, as
they are mutually exclusive.

Since 7.21.7, this option is superfluous since you can
specify a socks5 hostname proxy with -x, --proxy using a
socks5h:// protocol prefix.

Since 7.52.0, --preproxy can be used to specify a SOCKS
proxy at the same time -x, --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 this option is used several times, the last one will be
used.

Added in 7.18.0.
--socks5 Use the specified SOCKS5 proxy - but resolve the host name
locally. If the port number is not specified, it is
assumed at port 1080.

This option overrides any previous use of -x, --proxy, as
they are mutually exclusive.

Since 7.21.7, this option is superfluous since you can
specify a socks5 proxy with -x, --proxy using a socks5://
protocol prefix.

Since 7.52.0, --preproxy can be used to specify a SOCKS
proxy at the same time -x, --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 this option is used several times, the last one will be
used.

This option (as well as --socks4) does not work with IPV6,
FTPS or LDAP.

Added in 7.18.0.
-Y, --speed-limit If a download is slower than this given speed (in bytes
per second) for speed-time seconds it gets aborted. speed-
time is set with -y, --speed-time and is 30 if not set.

If this option is used several times, the last one will be
used.
-y, --speed-time If a download is slower than speed-limit bytes per second
during a speed-time period, the download gets aborted. If
speed-time is used, the default speed-limit will be 1
unless set with -Y, --speed-limit.

This option controls transfers and thus will not affect
slow connects etc. If this is a concern for you, try the
--connect-timeout option.

If this option is used several times, the last one will be
used.
--ssl-allow-beastThis option tells curl to not work around a security flaw
in the SSL3 and TLS1.0 protocols known as BEAST. If this
option isn't used, the SSL layer may use workarounds known
to cause interoperability problems with some older SSL
implementations. WARNING: this option loosens the SSL
security, and by using this flag you ask for exactly that.

Added in 7.25.0.
--ssl-no-revoke(Schannel) This option tells curl to disable certificate
revocation checks. WARNING: this option loosens the SSL
security, and by using this flag you ask for exactly that.

Added in 7.44.0.
--ssl-reqd(FTP IMAP POP3 SMTP) Require SSL/TLS for the connection.
Terminates the connection if the server doesn't support
SSL/TLS.

This option was formerly known as --ftp-ssl-reqd.

Added in 7.20.0.
--ssl(FTP IMAP POP3 SMTP) Try to use SSL/TLS for the
connection. Reverts to a non-secure connection if the
server doesn't support SSL/TLS. See also --ftp-ssl-
control and --ssl-reqd for different levels of encryption
required.

This option was formerly known as --ftp-ssl (Added in
7.11.0). That option name can still be used but will be
removed in a future version.

Added in 7.20.0.
-2, --sslv2(SSL) Forces curl to use SSL version 2 when negotiating
with a remote SSL server. Sometimes curl is built without
SSLv2 support. SSLv2 is widely considered insecure (see
RFC 6176).

See also --http1.1 and --http2. -2, --sslv2 requires that
the underlying libcurl was built to support TLS. This
option overrides -3, --sslv3 and -1, --tlsv1 and --tlsv1.1
and --tlsv1.2.
-3, --sslv3(SSL) Forces curl to use SSL version 3 when negotiating
with a remote SSL server. Sometimes curl is built without
SSLv3 support. SSLv3 is widely considered insecure (see
RFC 7568).

See also --http1.1 and --http2. -3, --sslv3 requires that
the underlying libcurl was built to support TLS. This
option overrides -2, --sslv2 and -1, --tlsv1 and --tlsv1.1
and --tlsv1.2.
--stderr Redirect all writes to stderr to the specified file
instead. If the file name is a plain '-', it is instead
written to stdout.

If this option is used several times, the last one will be
used.

See also -v, --verbose and -s, --silent.
--styled-outputEnables the automatic use of bold font styles when writing
HTTP headers to the terminal. Use --no-styled-output to
switch them off.

Added in 7.61.0.
--suppress-connect-headersWhen -p, --proxytunnel is used and a CONNECT request is
made don't output proxy CONNECT response headers. This
option is meant to be used with -D, --dump-header or -i,
--include which are used to show protocol headers in the
output. It has no effect on debug options such as -v,
--verbose or --trace, or any statistics.

See also -D, --dump-header, -i, --include and -p,
--proxytunnel.
--tcp-fastopenEnable use of TCP Fast Open (RFC7413).

Added in 7.49.0.
--tcp-nodelayTurn on the TCP_NODELAY option. See the
curl_easy_setopt(3) man page for details about this
option.

Since 7.50.2, curl sets this option by default and you
need to explicitly switch it off if you don't want it on.

Added in 7.11.2.
-t, --telnet-option Pass options to the telnet protocol. Supported options
are:

TTYPE= Sets the terminal type.

XDISPLOC= Sets the X display location.

NEW_ENV= Sets an environment variable.
--tftp-blksize (TFTP) Set TFTP BLKSIZE option (must be >512). This is the
block size that curl will try to use when transferring
data to or from a TFTP server. By default 512 bytes will
be used.

If this option is used several times, the last one will be
used.

Added in 7.20.0.
--tftp-no-options(TFTP) Tells curl not to send TFTP options requests.

This option improves interop with some legacy servers that
do not acknowledge or properly implement TFTP options.
When this option is used --tftp-blksize is ignored.

Added in 7.48.0.
-z, --time-cond (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 can be
all sorts of date strings or if it doesn't match any
internal ones, it is taken as a filename and tries to get
the modification date (mtime) from instead. See the
curl_getdate(3) 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 this option is used several times, the last one will be
used.
--tls-max (SSL) 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.

default
Use up to recommended TLS version.

1.0 Use up to TLSv1.0.

1.1 Use up to TLSv1.1.

1.2 Use up to TLSv1.2.

1.3 Use up to TLSv1.3.

See also –tlsv1.0, –tlsv1.1, –tlsv1.2 and –tlsv1.3. –tls-max requires that the underlying libcurl was built to support TLS.

Added in 7.54.0.

OptionsPurpose
--tls13-ciphers (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. If you are using a different
SSL backend you can try setting TLS 1.3 cipher suites by
using the --ciphers option.

If this option is used several times, the last one will be
used.
--tlsauthtype Set TLS authentication type. Currently, the only supported
option is "SRP", for TLS-SRP (RFC 5054). If --tlsuser and
--tlspassword are specified but --tlsauthtype 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.

Added in 7.21.4.
--tlspasswordSet password for use with the TLS authentication method
specified with --tlsauthtype. Requires that --tlsuser also
be set.

This doesn't work with TLS 1.3.

Added in 7.21.4.
--tlsuser Set username for use with the TLS authentication method
specified with --tlsauthtype. Requires that --tlspassword
also is set.

This doesn't work with TLS 1.3.

Added in 7.21.4.
--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, but behavior was inconsistent
depending on the TLS library. Use --tls-max if you want to
set a maximum TLS version.

Added in 7.34.0.
--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, but behavior was inconsistent
depending on the TLS library. Use --tls-max if you want to
set a maximum TLS version.

Added in 7.34.0.
--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, but behavior was inconsistent
depending on the TLS library. Use --tls-max if you want to
set a maximum TLS version.

Added in 7.34.0.
--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.

Added in 7.52.0.
-1, --tlsv1(SSL) Tells curl to use at least TLS version 1.x when
negotiating with a remote TLS server. That means TLS
version 1.0 or higher

See also --http1.1 and --http2. -1, --tlsv1 requires that
the underlying libcurl was built to support TLS. This
option overrides --tlsv1.1 and --tlsv1.2 and --tlsv1.3.
--tr-encoding(HTTP) Request a compressed Transfer-Encoding response
using one of the algorithms curl supports, and uncompress
the data while receiving it.

Added in 7.21.6.
--trace-ascii Enables a full trace dump of all incoming and outgoing
data, including descriptive information, to the given
output file. Use "-" as filename to have the output sent
to stdout.

This is very similar to --trace, 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.

If this option is used several times, the last one will be
used.

This option overrides --trace and -v, --verbose.
--trace-timePrepends a time stamp to each trace or verbose line that
curl displays.

Added in 7.14.0.
--trace Enables a full trace dump of all incoming and outgoing
data, including descriptive information, to the given
output file. Use "-" as filename to have the output sent
to stdout. Use "%" as filename to have the output sent to
stderr.

If this option is used several times, the last one will be
used.

This option overrides -v, --verbose and --trace-ascii.
--unix-socket (HTTP) Connect through this Unix domain socket, instead of
using the network.

Added in 7.40.0.
-T, --upload-file This transfers the specified local file to the remote URL.
If there is no file part in the specified URL, curl will
append the local file name. NOTE that you must use a
trailing / on the last directory to really prove to Curl
that there is no file name or curl will think that your
last directory name is the remote file name to use. That
will most likely cause the upload operation to fail. If
this is used on an HTTP(S) server, the PUT command will be
used.

Use the file name "-" (a single dash) to use stdin instead
of a given file. Alternately, the file name "." (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.

You can specify one -T, --upload-file for each URL on the
command line. Each -T, --upload-file + URL pair specifies
what to upload and to where. curl also supports "globbing"
of the -T, --upload-file argument, meaning that you can
upload multiple files to a single URL by using the same
URL globbing style supported in the URL, like this:

curl --upload-file "{file1,file2}" http://www.example.com

or even

curl -T "img[1-1000].png" ftp://ftp.example.com/upload/

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 will not transcode nor encode it
further in any way.
--url Specify a URL to fetch. This option is mostly handy when
you want to specify URL(s) in a config file.

If the given URL is missing a scheme name (such as
"http://" or "ftp://" etc) then curl will make a guess
based on the host. If the outermost sub-domain name
matches DICT, FTP, IMAP, LDAP, POP3 or SMTP then that
protocol will be used, otherwise HTTP will be used. Since
7.45.0 guessing can be disabled by setting a default
protocol, see --proto-default for details.

This option may be used any number of times. To control
where this URL is written, use the -o, --output or the -O,
--remote-name options.

Warning: On Windows, particular file:// accesses can be
converted to network accesses by the operating system.
Beware!
-B, --use-ascii(FTP LDAP) Enable ASCII transfer. 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.
-A, --user-agent (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 -H, --header or the --proxy-header options.

If you give an empty argument to -A, --user-agent (""), it
will remove the header completely from the request. If you
prefer a blank header, you can set it to a single space ("
").

If this option is used several times, the last one will be
used.
-u, --user Specify the user name and password to use for server
authentication. Overrides -n, --netrc and --netrc-
optional.

If you simply specify the user name, curl will prompt for
a password.

The user name and passwords are split up on the first
colon, which makes it impossible to use a colon in the
user name with this option. The password can, still.

On systems where it works, curl will hide 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 will still be visible for
a brief 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 user name,
in order for the server to successfully obtain a Kerberos
Ticket. If you don't then the initial authentication
handshake may fail.

When using NTLM, the user name can be specified simply as
the user name, 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 user name and password
from your environment by specifying a single colon with
this option: "-u :".

If this option is used several times, the last one will be
used.
-v, --verboseMakes curl verbose during the operation. Useful for
debugging and seeing what's 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, -i, --include
might be the option you're looking for.

If you think this option still doesn't give you enough
details, consider using --trace or --trace-ascii instead.

Use -s, --silent to make curl really quiet.

See also -i, --include. This option overrides --trace and
--trace-ascii.
-V, --versionDisplays 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 "Protocols:") shows all
protocols that libcurl reports to support.

The third line (starts with "Features:") shows specific
features libcurl reports to offer. Available features
include:

alt-svc
Support for the Alt-Svc: header is provided.

AsynchDNS
This curl uses asynchronous name resolves.
Asynchronous name resolves can be done using either
the c-ares or the threaded resolver backends.

brotli Support for automatic brotli compression over
HTTP(S).

CharConv
curl was built with support for character set
conversions (like EBCDIC)

Debug This curl uses a libcurl built with Debug. This
enables more error-tracking and memory debugging
etc. For curl-developers only!

gsasl The built-in SASL authentication includes
extensions to support SCRAM because libcurl was
built with libgsasl.

GSS-API
GSS-API is supported.

HSTS HSTS support is present.

HTTP2 HTTP/2 support has been built-in.

HTTP3 HTTP/3 support has been built-in.

HTTPS-proxy
This curl is built to support HTTPS proxy.

IDN This curl supports IDN - international domain
names.

IPv6 You can use IPv6 with this.

Kerberos
Kerberos V5 authentication is supported.

Largefile
This curl supports transfers of large files, files
larger than 2GB.

libz Automatic decompression (via gzip, deflate) of
compressed files over HTTP is supported.

Metalink
This curl supports Metalink.

MultiSSL
This curl supports multiple TLS backends.

NTLM NTLM authentication is supported.

NTLM_WB
NTLM delegation to winbind helper is supported.

PSL PSL is short for Public Suffix List and means that
this curl has been built with knowledge about
"public suffixes".

SPNEGO SPNEGO authentication is supported.

SSL SSL versions of various protocols are supported,
such as HTTPS, FTPS, POP3S and so on.

SSPI SSPI is supported.

TLS-SRP
SRP (Secure Remote Password) authentication is
supported for TLS.

TrackMemory
Debug memory tracking is supported.

Unicode
Unicode support on Windows.

UnixSockets
Unix sockets support is provided.

zstd Automatic decompression (via zstd) of compressed
files over HTTP is supported.
-w, --write-out 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 will be
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 will be written to standard output, but this
can be switched to standard error by using %{stderr}.

NOTE: The %-symbol is a special symbol in the
win32-environment, where all occurrences of % must be
doubled when using this option.

The variables available are:

content_type
The Content-Type of the requested document, if
there was any.

errormsg
The error message. (Added in 7.75.0)

exitcode
The numerical exitcode of the transfer. (Added in
7.75.0)

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 -O, --remote-name or -o, --output
option. It's most useful in combination with the
-J, --remote-header-name option. (Added in 7.26.0)

ftp_entry_path
The initial path curl ended up in when logging on
to the remote FTP server. (Added in 7.15.4)

http_code
The numerical response code that was found in the
last retrieved HTTP(S) or FTP(s) transfer. In
7.18.2 the alias response_code was added to show
the same info.

http_connect
The numerical code that was found in the last
response (from a proxy) to a curl CONNECT request.
(Added in 7.12.4)

http_version
The http version that was effectively used. (Added
in 7.50.0)

json A JSON object with all available keys.

local_ip
The IP address of the local end of the most
recently done connection - can be either IPv4 or
IPv6 (Added in 7.29.0)

local_port
The local port number of the most recently done
connection (Added in 7.29.0)

method The http method used in the most recent HTTP
request (Added in 7.72.0)

num_connects
Number of new connects made in the recent transfer.
(Added in 7.12.3)

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)

num_redirects
Number of redirects that were followed in the
request. (Added in 7.12.3)

onerror
The rest of the output is only shown if the
transfer returned a non-zero error (Added in
7.75.0)

proxy_ssl_verify_result
The result of the HTTPS proxy's SSL peer
certificate verification that was requested. 0
means the verification was successful. (Added in
7.52.0)

redirect_url
When an HTTP request was made without -L,
--location to follow redirects (or when --max-redir
is met), this variable will show the actual URL a
redirect would have gone to. (Added in 7.18.2)

referer
The Referer: header, if there was any. (Added in
7.76.0)

remote_ip
The remote IP address of the most recently done
connection - can be either IPv4 or IPv6 (Added in
7.29.0)

remote_port
The remote port number of the most recently done
connection (Added in 7.29.0)

response_code
The numerical response code that was found in the
last transfer (formerly known as "http_code").
(Added in 7.18.2)

scheme The URL scheme (sometimes called protocol) that was
effectively used (Added in 7.52.0)

size_download
The total amount of bytes that were downloaded.

size_header
The total amount of bytes of the downloaded
headers.

size_request
The total amount of bytes that were sent in the
HTTP request.

size_upload
The total amount of bytes that were uploaded.

speed_download
The average download speed that curl measured for
the complete download. Bytes per second.

speed_upload
The average upload speed that curl measured for the
complete upload. Bytes per second.

ssl_verify_result
The result of the SSL peer certificate verification
that was requested. 0 means the verification was
successful. (Added in 7.19.0)

stderr From this point on, the -w, --write-out output will
be written to standard error. (Added in 7.63.0)

stdout From this point on, the -w, --write-out output will
be written to standard output. This is the
default, but can be used to switch back after
switching to stderr. (Added in 7.63.0)

time_appconnect
The time, in seconds, it took from the start until
the SSL/SSH/etc connect/handshake to the remote
host was completed. (Added in 7.19.0)

time_connect
The time, in seconds, it took from the start until
the TCP connect to the remote host (or proxy) was
completed.

time_namelookup
The time, in seconds, it took from the start until
the name resolving was completed.

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.

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. (Added in 7.12.3)

time_starttransfer
The time, in seconds, it took from the start until
the first byte was just about to be transferred.
This includes time_pretransfer and also the time
the server needed to calculate the result.

time_total
The total time, in seconds, that the full operation
lasted.

url The URL that was fetched. (Added in 7.75.0)

urlnum The URL index number of this transfer, 0-indexed.
(Added in 7.75.0)

url_effective
The URL that was fetched last. This is most
meaningful if you've told curl to follow location:
headers.

If this option is used several times, the last one will be
used.
--xattrWhen saving output to a file, this option tells curl to
store certain 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.

FILES

       ~/.curlrc
              Default config file, see -K, --config for details.

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 -x, --proxy option.

       http_proxy [protocol://]<host>[:port]
              Sets the proxy server to use for HTTP.

       HTTPS_PROXY [protocol://]<host>[:port]
              Sets the proxy server to use for HTTPS.

       [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.

       ALL_PROXY [protocol://]<host>[:port]
              Sets the proxy server to use if no protocol-specific proxy
              is set.

       NO_PROXY <comma-separated list of hosts/domains>
              list of host names that shouldn't go through any proxy. If
              set to an asterisk '*' 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 -x, --proxy option. That is
              NO_PROXY=direct.example.com curl -x
              http://proxy.example.com http://direct.example.com
              accesses the target URL directly, and
              NO_PROXY=direct.example.com curl -x
              http://proxy.example.com http://somewhere.example.com
              accesses the target URL through the proxy.

              The list of host names can also be include numerical IP
              addresses, and IPv6 versions should then be given without
              enclosing brackets.

              IPv6 numerical addresses are compared as strings, so they
              will only match if the representations are the same: "::1"
              is the same as "::0:1" but they don't match.

       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 isn't a built-in
              alternative will make curl stay with the default.

              SSL backend names (case-insensitive): bearssl, gnutls,
              gskit, mbedtls, mesalink, nss, openssl, rustls, schannel,
              secure-transport, wolfssl

       QLOGDIR <directory name>
              If curl was built with HTTP/3 support, setting this
              environment variable to a local directory will make curl
              produce qlogs 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 both QUIC
              backends.

       SSLKEYLOGFILE <file name>
              If you set this environment variable to a file name, curl
              will store 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, BoringSSL, GnuTLS, NSS and wolfSSL.

EXIT CODES

There are a bunch of different error codes and their corresponding error messages that may appear during bad conditions. At the time of this writing, the exit codes are:

Error CodesError Message
1Unsupported protocol. This build of curl has no support for this protocol.
2Failed to initialize.
3URL malformed. The syntax was not correct.
4A 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!
5Couldn't resolve proxy. The given proxy host could not be resolved.
6Couldn't resolve host. The given remote host was not resolved.
7Failed to connect to host.
8Weird server reply. The server sent data curl couldn't parse.
9FTP 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 doesn't exist on the server.
10FTP 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.
11FTP weird PASS reply. Curl couldn't parse the reply sent to the PASS request.
12During an active FTP session while waiting for the server to connect back to curl, the timeout expired.
13FTP weird PASV reply, Curl couldn't parse the reply sent to the PASV request.
14FTP weird 227 format. Curl couldn't parse the 227-line the server sent.
15FTP can't get host. Couldn't resolve the host IP we got in the 227-line.
16HTTP/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.
17FTP couldn't set binary. Couldn't change transfer method to binary.
18Partial file. Only a part of the file was transferred.
19FTP couldn't download/access the given file, the RETR (or similar) command failed.
21FTP quote error. A quote command returned error from the server.
22HTTP 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 -f, --fail is used.
23Write error. Curl couldn't write data to a local filesystem or similar.
25FTP couldn't STOR file. The server denied the STOR operation, used for FTP uploading.
26Read error. Various reading problems.
27Out of memory. A memory allocation request failed.
28Operation timeout. The specified time-out period was reached according to the conditions.
30FTP PORT failed. The PORT command failed. Not all FTP servers support the PORT command, try doing a transfer using PASV instead!
31FTP couldn't use REST. The REST command failed. This command is used for resumed FTP transfers.
33HTTP range error. The range "command" didn't work.
34HTTP post error. Internal post-request generation error.
35SSL connect error. The SSL handshaking failed.
36Bad download resume. Couldn't continue an earlier aborted download.
37FILE couldn't read file. Failed to open the file. Permissions?
38LDAP cannot bind. LDAP bind operation failed.
39LDAP search failed.
41Function not found. A required LDAP function was not found.
42Aborted by callback. An application told curl to abort the operation.
43Internal error. A function was called with a bad parameter.
45Interface error. A specified outgoing interface could not be used.
47Too many redirects. When following redirects, curl hit the maximum amount.
48Unknown 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!
49Malformed telnet option.
51The peer's SSL certificate or SSH MD5 fingerprint was not OK.
52The server didn't reply anything, which here is considered an error.
53SSL crypto engine not found.
54Cannot set SSL crypto engine as default.
55Failed sending network data.
56Failure in receiving network data.
58Problem with the local certificate.
59Couldn't use specified SSL cipher.
60Peer certificate cannot be authenticated with known CA certificates.
61Unrecognized transfer encoding.
62Invalid LDAP URL.
63Maximum file size exceeded.
64Requested FTP SSL level failed.
65Sending the data requires a rewind that failed.
66Failed to initialise SSL Engine.
67The user name, password, or similar was not accepted and curl failed to log in.
68File not found on TFTP server.
69Permission problem on TFTP server.
70Out of disk space on TFTP server.
71Illegal TFTP operation.
72Unknown TFTP transfer ID.
73File already exists (TFTP).
74No such user (TFTP).
75Character conversion failed.
76Character conversion functions required.
77Problem with reading the SSL CA cert (path? access rights?).
78The resource referenced in the URL does not exist.
79An unspecified error occurred during the SSH session.
80Failed to shut down the SSL connection.
82Could not load CRL file, missing or wrong format (added in 7.19.0).
83Issuer check failed (added in 7.19.0).
84The FTP PRET command failed
85RTSP: mismatch of CSeq numbers
86RTSP: mismatch of Session Identifiers
87unable to parse FTP file list
88FTP chunk callback reported error
89No connection available, the session will be queued
90SSL public key does not matched pinned public key
91Invalid SSL certificate status.
92Stream error in HTTP/2 framing layer.
XXMore error codes will appear here in future releases. The existing ones are meant to never change.

AUTHORS / CONTRIBUTORS      

Daniel Stenberg is the main author, but the whole list of contributors is found in the separate THANKS file.

Back to Command Help page.

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