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curl(1) Curl Manual curl(1)

NAME
curl - transfer a URL

SYNOPSIS
curl [options] [URL...]

DESCRIPTION
curl is a tool to transfer data from or to a server, using one of the supported protocols (HTTP, HTTPS, FTP, FTPS, SCP,
SFTP, TFTP, DICT, TELNET, LDAP or FILE). 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 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. See libcurl(3) for details.

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 as in:

http://site.{one,two,three}.com

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

ftp://ftp.numericals.com/file[1-100].txt
ftp://ftp.numericals.com/file[001-100].txt (with leading zeros)
ftp://ftp.letters.com/file[a-z].txt

No nesting of the sequences is supported at the moment, but you can use several ones next to each other:

http://any.org/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.

Since curl 7.15.1 you can also specify a step counter for the ranges, so that you can get every Nth number or letter:

http://www.numericals.com/file[1-100:10].txt
http://www.letters.com/file[a-z:2].txt

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.

However, since curl displays this data to the terminal by default, 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 [file] 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, -# is your friend.

OPTIONS
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.)

-a/--append
(FTP/SFTP) When used in an upload, this will tell curl to append to the target file instead of overwriting it. If
the file doesn't exist, it will be created. Note that this flag is ignored by some SSH servers (including
OpenSSH).

-A/--user-agent <agent string>
(HTTP) Specify the User-Agent string to send to the HTTP server. Some badly done CGIs fail if this field isn't set
to "Mozilla/4.0". To encode blanks in the string, surround the string with single quote marks. This can also be
set with the -H/--header option of course.

If this option is set more than once, the last one will be the one that's used.

--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.

Note that 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.

-b/--cookie <name=data>
(HTTP) Pass the data to the HTTP server as a cookie. 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 line, it is treated as a filename to use to read previously stored cookie lines
from, which should be used in this session if they match. Using this method also activates the "cookie parser"
which will make curl record incoming cookies too, which may be handy if you're using this in combination with the
-L/--location option. The file format of the file to read cookies from should be plain HTTP headers or the
Netscape/Mozilla cookie file format.

NOTE that the file specified with -b/--cookie is only used as input. No cookies will be stored in the file. To
store cookies, use the -c/--cookie-jar option or you could even save the HTTP headers to a file using -D/--dump-
header!

If this option is set more than once, the last one will be the one that's used.

-B/--use-ascii
Enable ASCII transfer when using FTP or LDAP. For FTP, this can also be enforced by using an URL that ends with
";type=A". This option causes data sent to stdout to be in text mode for win32 systems.

--basic
(HTTP) Tells curl to use HTTP Basic authentication. 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).

--ciphers <list of ciphers>
(SSL) 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: http://www.openssl.org/docs/apps/ciphers.html

NSS ciphers are done differently than OpenSSL and GnuTLS. The full list of NSS ciphers is in the NSSCipherSuite
entry at this URL: http://directory.fedora.redhat.com/docs/mod_nss.html#Directives

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

--compressed
(HTTP) Request a compressed response using one of the algorithms libcurl supports, and return the uncompressed
document. If this option is used and the server sends an unsupported encoding, curl will report an error.

--connect-timeout <seconds>
Maximum time in seconds that you allow the connection to the server to take. This only limits the connection
phase, once curl has connected this option is of no more use. See also the -m/--max-time option.

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

-c/--cookie-jar <file name>
Specify to which file you want curl to write all cookies after a completed operation. Curl writes all cookies pre-
viously read from a specified file as well as all cookies received from remote server(s). If no cookies are known,
no file 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.

NOTE 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 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.

-C/--continue-at <offset>
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 out-
put/input files to figure that out.

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

--create-dirs
When used in conjunction with the -o option, curl will create the necessary local directory hierarchy as needed.
This option creates the dirs mentioned with the -o option, nothing else. If the -o file name uses no dir or if the
dirs it mentions already exist, no dir will be created.

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

--crlf (FTP) Convert LF to CRLF in upload. Useful for MVS (OS/390).

--crlfile <file>
(HTTPS/FTPS) 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)

-d/--data <data>
(HTTP) 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.

-d/--data is the same as --data-ascii. 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. The contents of the file must already be URL-encoded. Multiple files can also
be specified. Posting data from a file named 'foobar' would thus be done with --data @foobar.

--data-binary <data>
(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
--data-ascii does, except that newlines are preserved and conversions are never done.

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

--data-urlencode <data>
(HTTP) This posts data, similar to the other --data options with the exception that this performs URL-encoding.
(Added in 7.18.0)

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:

content
This 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!

=content
This will make curl URL-encode the content and pass that on. The preceding = symbol is not included in the
data.

name=content
This will make curl URL-encode the content part and pass that on. Note that the name part is expected to be
URL-encoded already.

@filename
This will make curl load data from the given file (including any newlines), URL-encode that data and pass
it on in the POST.

name@filename
This 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.

--delegation LEVEL
Set LEVEL to tell the server what it is allowed to delegate when it comes to user credentials. Used with GSS/ker-
beros.

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 a authentication 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 pass-
word. See also --ntlm, --negotiate and --anyauth for related options.

If this option is used several times, the following occurrences make no difference.

--disable-eprt
(FTP) Tell curl to disable the use of the EPRT and LPRT commands when doing active FTP transfers. Curl will nor-
mally 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.

Since curl 7.19.0, --eprt can be used to explicitly enable EPRT again and --no-eprt is an alias for --disable-
eprt.

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) 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.

Since curl 7.19.0, --epsv can be used to explicitly enable EPRT again and --no-epsv is an alias for --disable-
epsv.

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

-D/--dump-header <file>
Write the protocol headers to the specified file.

This option is handy to use when you want to store the headers that a 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 however a better way to store cookies.

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.

-e/--referer <URL>
(HTTP) Sends the "Referer 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 --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 --referer.

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

--engine <name>
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.

--environment
(RISC OS ONLY) Sets a range of environment variables, using the names the -w option supports, to allow easier
extraction of useful information after having run curl.

--egd-file <file>
(SSL) Specify the path name to the Entropy Gathering Daemon socket. The socket is used to seed the random engine
for SSL connections. See also the --random-file option.

-E/--cert <certificate[:password]>
(SSL) Tells curl to use the specified certificate file when getting a file with HTTPS or FTPS. The certificate
must be in PEM format. 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 private certificate concatenated!
See --cert and --key to specify them independently.

If curl is built against the NSS SSL library then this option tells 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 this option is used several times, the last one will be used.

--cert-type <type>
(SSL) Tells curl what certificate type the provided certificate is in. PEM, DER and ENG are recognized types. If
not specified, PEM is assumed.

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

--cacert <CA certificate>
(SSL) Tells curl to use the specified certificate file to verify the peer. The file may contain multiple CA cer-
tificates. 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 then this option tells curl the nickname of the CA 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 this option is used several times, the last one will be used.

--capath <CA certificate directory>
(SSL) Tells curl to use the specified certificate directory to verify the peer. The certificates must be in PEM
format, and the directory must have been processed using the c_rehash utility supplied with openssl. Using --cap-
ath can allow curl to make SSL-connections much more efficiently than using --cacert if the --cacert file contains
many CA certificates.

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

-f/--fail
(HTTP) Fail silently (no output at all) on server errors. This is mostly done to better enable scripts etc to bet-
ter deal with failed attempts. In normal cases when a 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, espe-
cially when authentication is involved (response codes 401 and 407).

--ftp-account [data]
(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. (Added in 7.13.0)

If this option is used twice, the second will override the previous use.

--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.

--ftp-method [method]
(FTP) Control what method curl should use to reach a file on a 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 RFC1738 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 mul-
ticwd case). This is somewhat more standards compliant than 'nocwd' but without the full penalty of 'multi-
cwd'.
(Added in 7.15.1)

--ftp-pasv
(FTP) Use passive mode for the data conection. Passive is the internal default behavior, but using this option can
be used to override a previous -P/-ftp-port option. (Added in 7.11.0)

If this option is used several times, the following occurrences make no difference. 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.

--ftp-alternative-to-user <command>
(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-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 connec-
tion. (Added in 7.14.2)

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

--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.x)

--ssl (FTP, POP3, IMAP, 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.
(Added in 7.20.0)

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

--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)

--ssl-reqd
(FTP, POP3, IMAP, SMTP) Require SSL/TLS for the connection. Terminates the connection if the server doesn't sup-
port SSL/TLS. (Added in 7.20.0)

This option was formerly known as --ftp-ssl-reqd (added in 7.15.5) and that can still be used but will be removed
in a future version.

--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 --ftp-ssl-ccc-mode for other modes. (Added in 7.16.1)

--ftp-ssl-ccc-mode [active/passive]
(FTP) Use CCC (Clear Command Channel) 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 initi-
ates the shutdown and waits for a reply from the server. (Added in 7.16.2)

-F/--form <name=content>
(HTTP) 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 RFC2388. 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.

Example, to send your password file to the server, where 'password' is the name of the form-field to which
/etc/passwd will be the input:

curl -F password=@/etc/passwd www.mypasswords.com

To read the file's content from stdin instead of a file, use - where the file name should've been. This goes for
both @ and < constructs.

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" url.com

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

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

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

See further examples and details in the MANUAL.

This option can be used multiple times.

--form-string <name=string>
(HTTP) Similar to --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 --form if
there's any possibility that the string value may accidentally trigger the '@' or '<' features of --form.

-g/--globoff
This 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.

-G/--get
When used, this option will make all data specified with -d/--data or --data-binary to be used in a 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, the POST data will instead be appended to the URL with a HEAD request.

If this option is used several times, the following occurrences make no difference. This is because undoing a GET
doesn't make sense, but you should then instead enforce the alternative method you prefer.

-h/--help
Usage help.

-H/--header <header>
(HTTP) Extra header to use when getting a web page. 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 nor-
mally 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:".

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.

See also the -A/--user-agent and -e/--referer options.

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

--hostpubmd5 <md5>
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. This option is only for SCP
and SFTP transfers. (Added in 7.17.1)

--ignore-content-length
(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.

-i/--include
(HTTP) Include the HTTP-header in the output. The HTTP-header includes things like server-name, date of the docu-
ment, HTTP-version and more...

--interface <name>
Perform an operation using a specified interface. You can enter interface name, IP address or host name. An exam-
ple could look like:

curl --interface eth0:1 http://www.netscape.com/

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

-I/--head
(HTTP/FTP/FILE) Fetch the HTTP-header only! HTTP-servers feature the command HEAD which this uses to get nothing
but the header of a document. When used on a FTP or FILE file, curl displays the file size and last modification
time only.

-j/--junk-session-cookies
(HTTP) When curl is told to read cookies from a given file, this option will make it discard all "session cook-
ies". 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.

-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.

-k/--insecure
(SSL) This option explicitly allows curl to perform "insecure" SSL connections and transfers. All SSL connections
are attempted to be made secure by using the CA certificate bundle installed by default. This makes all connec-
tions considered "insecure" fail unless -k/--insecure is used.

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

--keepalive-time <seconds>
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. (Added in 7.18.0)

If this option is used multiple times, the last occurrence sets the amount.

--key <key>
(SSL/SSH) Private key file name. Allows you to provide your private key in this separate file.

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

--key-type <type>
(SSL) Private key file type. Specify which type your --key provided private key is. DER, PEM, and ENG are sup-
ported. If not specified, PEM is assumed.

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

--krb <level>
(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.

This option requires a library built with kerberos4 or GSSAPI (GSS-Negotiate) support. This is not very common.
Use -V/--version to see if your curl supports it.

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

-K/--config <config file>
Specify which config file to read curl arguments from. The config file is a text file in which command line argu-
ments can be written which then will be used as if they were written on the actual command line. Options and their
parameters must be specified on the same config file line, separated by whitespace, colon, the equals sign or any
combination thereof (however, the preferred separator is the equals sign). If the parameter is to contain white-
space, 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 phys-
ical 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 = "http://curl.haxx.se/docs/"

Long option names can optionally be given in the config file without the initial double dashes.

When curl is invoked, it always (unless -q 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) curl tries to find the "home dir": It first checks for the CURL_HOME and then the HOME environment variables.
Failing that, it uses getpwuid() on UNIX-like systems (which returns the home dir given the current user in your
system). On Windows, it then checks for the APPDATA variable, or as a last resort the '%USERPROFILE%\Application
Data'.

2) 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 = "curl.haxx.se"
output = "curlhere.html"
user-agent = "superagent/1.0"

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

This option can be used multiple times to load multiple config files.

--libcurl <file>
Append this option to any ordinary curl command line, and you will get a libcurl-using source code written to the
file that does the equivalent of what your command-line operation does!

NOTE: this does not properly support -F and the sending of multipart formposts, so in those cases the output pro-
gram will be missing necessary calls to curl_formadd(3), and possibly more.

If this option is used several times, the last given file name will be used. (Added in 7.16.1)

--limit-rate <speed>
Specify the maximum transfer rate you want curl to use. This feature is useful if you have a limited pipe and
you'd like your transfer not to use your entire bandwidth.

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.

The given rate is the average speed counted during the entire transfer. It means that curl might use higher trans-
fer speeds in short bursts, but over time it uses no more than the given rate.

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) When listing an FTP directory, this switch forces a name-only view. Especially useful if you want to
machine-parse the contents of an FTP directory since the normal directory view doesn't use a standard look or for-
mat.

This option causes an FTP NLST command to be sent. Some FTP servers list only files in their response to NLST;
they do not include subdirectories and symbolic links.

--local-port <num>[-num]
Set a preferred number or range 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)

-L/--location
(HTTP/HTTPS) 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 the request is not a plain GET (for example POST or PUT), it will do the follow-
ing 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.

--location-trusted
(HTTP/HTTPS) Like -L/--location, but will allow sending the name + password to all hosts that the site may redi-
rect 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).

--mail-rcpt <address>
(SMTP) Specify a single address that the given mail should get sent to. This option can be used multiple times to
specify many recipients.

(Added in 7.20.0)

--mail-from <address>
(SMTP) Specify a single address that the given mail should get sent from.

(Added in 7.20.0)

--max-filesize <bytes>
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.

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.

-m/--max-time <seconds>
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. See also the --connect-timeout option.

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

-M/--manual
Manual. Display the huge help text.

-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(4) or 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

--netrc-optional
Very similar to --netrc, but this option makes the .netrc usage optional and not mandatory as the --netrc option
does.

--negotiate
(HTTP) Enables GSS-Negotiate authentication. The GSS-Negotiate method was designed by Microsoft and is used in
their web applications. It is primarily meant as a support for Kerberos5 authentication but may be also used along
with another authentication method. For more information see IETF draft draft-brezak-spnego-http-04.txt.

If you want to enable Negotiate for your proxy authentication, then use --proxy-negotiate.

This option requires a library built with GSSAPI support. This is not very common. Use -V/--version to see if your
version supports GSS-Negotiate.

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

If this option is used several times, the following occurrences make no difference.

-N/--no-buffer
Disables 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-keepalive
Disables the use of keepalive messages on the TCP connection, as by default curl enables them.

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

--no-sessionid
(SSL) 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 implementa-
tions in the wild that may require you to disable this in order for you to succeed. (Added in 7.16.0)

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

--noproxy <no-proxy-list>
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. (Added in 7.19.4).

--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.

This option requires a library built with SSL support. Use -V/--version to see if your curl supports NTLM.

If this option is used several times, the following occurrences make no difference.

-o/--output <file>
Write output to <file> instead of stdout. If you are using {} or [] to fetch multiple documents, you can use '#'
followed by a number in the <file> specifier. That variable will be replaced with the current string for the URL
being fetched. Like in:

curl http://{one,two}.site.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.

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.

-O/--remote-name
Write output to a local file named like the remote file we get. (Only the file part of the remote file is used,
the path is cut off.)

The remote file name to use for saving is extracted from the given URL, nothing else.

You may use this option as many times as the number of URLs you have.

--remote-name-all
This 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)

--pass <phrase>
(SSL/SSH) Passphrase for the private key

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

--post301
Tells curl to respect RFC 2616/10.3.2 and not convert POST requests into GET requests when following a 301 redi-
rection. The non-RFC behaviour 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 mean-
ingful only when using -L/--location (Added in 7.17.1)

--post302
Tells curl to respect RFC 2616/10.3.2 and not convert POST requests into GET requests when following a 302 redi-
rection. The non-RFC behaviour 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 mean-
ingful only when using -L/--location (Added in 7.19.1)

--proto <protocols>
Tells curl to use the listed protocols for its initial retrieval. 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 modi-
fiers 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 subse-
quent 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 dan-
gerous 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.

(Added in 7.20.2)

--proto-redir <protocols>
Tells curl to use the listed protocols after a redirect. See --proto for how protocols are represented.

(Added in 7.20.2)

--proxy-anyauth
Tells curl to pick a suitable authentication method when communicating with the given proxy. This might cause an
extra request/response round-trip. (Added in 7.13.2)

--proxy-basic
Tells 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.

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

--proxy-negotiate
Tells curl to use HTTP Negotiate authentication when communicating with the given proxy. Use --negotiate for
enabling HTTP Negotiate with a remote host. (Added in 7.17.1)

--proxy-ntlm
Tells curl to use HTTP NTLM authentication when communicating with the given proxy. Use --ntlm for enabling NTLM
with a remote host.

--proxy1.0 <proxyhost[:port]>
Use the specified HTTP 1.0 proxy. If the port number is not specified, it is assumed at port 1080.

The only difference between this and the HTTP proxy option (-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/--proxytunnel
When an HTTP proxy is used (-x/--proxy), this option will cause non-HTTP protocols to attempt to tunnel through
the proxy instead of merely using it to do HTTP-like operations. 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.

--pubkey <key>
(SSH) 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.

-P/--ftp-port <address>
(FTP) Reverses the default initiator/listener roles when connecting with FTP. This switch makes curl use active
mode. In practice, 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. <address> should be one of:

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

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

host name
i.e "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++.

Starting in 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.

-q If 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.

-Q/--quote <command>
(FTP/SFTP) Send an arbitrary command to the remote FTP or SFTP server. Quote commands are sent BEFORE the transfer
takes place (just after the initial 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 libcurl 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 RFC959 defines to FTP servers, or
one of the commands listed below to SFTP servers. This option can be used multiple times.

SFTP is a binary protocol. Unlike for FTP, libcurl interprets SFTP quote commands before sending them to the
server. Following is the list of all supported SFTP quote commands:

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.

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 <file>
(SSL) Specify the path name to file containing what will be considered as random data. The data is used to seed
the random engine for SSL connections. See also the --egd-file option.

-r/--range <range>
(HTTP/FTP/SFTP/FILE) Retrieve a byte range (i.e a partial document) from a 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(*)(H)

500-700,600-799
specifies 300 bytes from offset 500(H)

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

(*) = NOTE that this will cause the server to reply with a multipart response!

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 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)

-R/--remote-time
When used, this will make libcurl attempt to figure out the timestamp of the remote file, and if that is available
make the local file get that same timestamp.

--retry <num>
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 5xx 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. (Added in 7.12.3)

If this option is used multiple times, the last occurrence decide the amount.

--retry-delay <seconds>
Make curl sleep this amount of time before each retry when a transfer has failed with a transient error (it
changes the default backoff time algorithm between retries). This option is only interesting if --retry is also
used. Setting this delay to zero will make curl use the default backoff time. (Added in 7.12.3)

If this option is used multiple times, the last occurrence determines the amount.

--retry-max-time <seconds>
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. (Added in 7.12.3)

If this option is used multiple times, the last occurrence determines the amount.

-s/--silent
Silent or quiet mode. Don't show progress meter or error messages. Makes Curl mute.

-S/--show-error
When used with -s it makes curl show an error message if it fails.

--socks4 <host[:port]>
Use the specified SOCKS4 proxy. If the port number is not specified, it is assumed at port 1080. (Added in 7.15.2)

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

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

--socks4a <host[:port]>
Use the specified SOCKS4a proxy. If the port number is not specified, it is assumed at port 1080. (Added in
7.18.0)

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

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

--socks5-hostname <host[:port]>
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. (Added in 7.18.0)

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

If this option is used several times, the last one will be used. (This option was previously wrongly documented
and used as --socks without the number appended.)

--socks5 <host[:port]>
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.

If this option is used several times, the last one will be used. (This option was previously wrongly documented
and used as --socks without the number appended.)

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

--socks5-gssapi-service <servicename>
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 princpal name.
(Added in 7.19.4).

--socks5-gssapi-nec
As part of the gssapi negotiation a protection mode is negotiated. The rfc1961 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 unpro-
tected exchange of the protection mode negotiation. (Added in 7.19.4).

--stderr <file>
Redirect all writes to stderr to the specified file instead. If the file name is a plain '-', it is instead writ-
ten to stdout. This option has no point when you're using a shell with decent redirecting capabilities.

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

--tcp-nodelay
Turn on the TCP_NODELAY option. See the curl_easy_setopt(3) man page for details about this option. (Added in
7.11.2)

-t/--telnet-option <OPT=val>
Pass options to the telnet protocol. Supported options are:

TTYPE=<term> Sets the terminal type.

XDISPLOC=<X display> Sets the X display location.

NEW_ENV=<var,val> Sets an environment variable.

--tftp-blksize <value>
(TFTP) Set TFTP BLKSIZE option (must be >512). This is the block size that curl will try to use when tranferring
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)

-T/--upload-file <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 a 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 for each URL on the command line. Each -T + URL pair specifies what to upload and to where.
curl also supports "globbing" of the -T 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 -T "{file1,file2}" http://www.uploadtothissite.com

or even

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

--trace <file>
Enables a full trace dump of all incoming and outgoing data, including descriptive information, to the given out-
put file. Use "-" as filename to have the output sent to stdout.

This option overrides previous uses of -v/--verbose or --trace-ascii.

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

--trace-ascii <file>
Enables a full trace dump of all incoming and outgoing data, including descriptive information, to the given out-
put 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.

This option overrides previous uses of -v/--verbose or --trace.

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

--trace-time
Prepends a time stamp to each trace or verbose line that curl displays. (Added in 7.14.0)

-u/--user <user:password>
Specify the user name and password to use for server authentication. Overrides -n/--netrc and --netrc-optional.

If you just give the user name (without entering a colon) curl will prompt for a password.

If you use an SSPI-enabled curl binary and do NTLM authentication, you can force curl to pick up the user name and
password from your environment by simply specifying a single colon with this option: "-u :".

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

-U/--proxy-user <user:password>
Specify the user name and password to use for proxy authentication.

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

--url <URL>
Specify a URL to fetch. This option is mostly handy when you want to specify URL(s) in a config file.

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.

-v/--verbose
Makes the fetching more verbose/talkative. Mostly useful for debugging. 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.

Note that 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.

This option overrides previous uses of --trace-ascii or --trace.

Use -S/--silent to make curl quiet.

-V/--version
Displays information about curl and the libcurl version it uses.

The first line includes the full version of curl, libcurl and other 3rd party libraries linked with the exe-
cutable.

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:

IPv6 You can use IPv6 with this.

krb4 Krb4 for FTP is supported.

SSL HTTPS and FTPS are supported.

libz Automatic decompression of compressed files over HTTP is supported.

NTLM NTLM authentication is supported.

GSS-Negotiate
Negotiate authentication and krb5 for FTP is supported.

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

AsynchDNS
This curl uses asynchronous name resolves.

SPNEGO SPNEGO Negotiate authentication is supported.

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

IDN This curl supports IDN - international domain names.

SSPI SSPI is supported. If you use NTLM and set a blank user name, curl will authenticate with your current user
and password.

-w/--write-out <format>
Defines what to display on stdout after a completed and successful operation. The format is a string that may con-
tain plain text mixed with any number of variables. The string can be specified as "string", to get read from a
particular file you specify it "@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.

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 at this point are:

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

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)

time_total The total time, in seconds, that the full operation lasted. The time will be displayed with mil-
lisecond resolution.

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

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

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_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 include 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.

size_download The total amount of bytes that were downloaded.

size_upload The total amount of bytes that were uploaded.

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.

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.

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

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

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

redirect_url When a HTTP request was made without -L to follow redirects, this variable will show the actual URL
a redirect would take you to. (Added in 7.18.2)

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

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)

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

-x/--proxy <proxyhost[:port]>
Use the specified HTTP proxy. If the port number is not specified, it is assumed at port 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.

Note that all operations that are performed over a 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 done with the -p/--proxytunnel option.

Starting with 7.14.1, 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.

-X/--request <command>
(HTTP) Specifies a custom request method to use when communicating with the HTTP server. The specified request
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.

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

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

-y/--speed-time <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.

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.

-Y/--speed-limit <speed>
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 and is 30 if not set.

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

-z/--time-cond <date expression>
(HTTP/FTP) Request a file that has been modified later than the given time and date, or one that has been modified
before that time. The date expression can be all sorts of date strings or if it doesn't match any internal ones,
it tries to get the time from a given file name 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.

--max-redirs <num>
Set maximum number of redirection-followings allowed. If -L/--location is used, this option can be used to prevent
curl from following redirections "in absurdum". By default, the limit is set to 50 redirections. Set this option
to -1 to make it limitless.

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

-0/--http1.0
(HTTP) Forces curl to issue its requests using HTTP 1.0 instead of using its internally preferred: HTTP 1.1.

-1/--tlsv1
(SSL) Forces curl to use TLS version 1 when negotiating with a remote TLS server.

-2/--sslv2
(SSL) Forces curl to use SSL version 2 when negotiating with a remote SSL server.

-3/--sslv3
(SSL) Forces curl to use SSL version 3 when negotiating with a remote SSL server.

-4/--ipv4
If libcurl is capable of resolving an address to multiple IP versions (which it is if it is IPv6-capable), this
option tells libcurl to resolve names to IPv4 addresses only.

-6/--ipv6
If libcurl is capable of resolving an address to multiple IP versions (which it is if it is IPv6-capable), this
option tells libcurl to resolve names to IPv6 addresses only.

-#/--progress-bar
Make curl display progress information as a progress bar instead of the default statistics.

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.

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.

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

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>
list of host names that shouldn't go through any proxy. If set to a asterisk '*' only, it matches all hosts.

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:

1 Unsupported protocol. This build of curl has no support for this protocol.

2 Failed to initialize.

3 URL malformed. The syntax was not correct.

5 Couldn't resolve proxy. The given proxy host could not be resolved.

6 Couldn't resolve host. The given remote host was not resolved.

7 Failed to connect to host.

8 FTP weird server reply. The server sent data curl couldn't parse.

9 FTP access denied. The server denied login or denied access to the particular resource or directory you wanted to
reach. Most often you tried to change to a directory that doesn't exist on the server.

11 FTP weird PASS reply. Curl couldn't parse the reply sent to the PASS request.

13 FTP weird PASV reply, Curl couldn't parse the reply sent to the PASV request.

14 FTP weird 227 format. Curl couldn't parse the 227-line the server sent.

15 FTP can't get host. Couldn't resolve the host IP we got in the 227-line.

17 FTP couldn't set binary. Couldn't change transfer method to binary.

18 Partial file. Only a part of the file was transferred.

19 FTP couldn't download/access the given file, the RETR (or similar) command failed.

21 FTP quote error. A quote command returned error from the server.

22 HTTP page not retrieved. The requested url was not found or returned another error with the HTTP error code being
400 or above. This return code only appears if -f/--fail is used.

23 Write error. Curl couldn't write data to a local filesystem or similar.

25 FTP couldn't STOR file. The server denied the STOR operation, used for FTP uploading.

26 Read error. Various reading problems.

27 Out of memory. A memory allocation request failed.

28 Operation timeout. The specified time-out period was reached according to the conditions.

30 FTP PORT failed. The PORT command failed. Not all FTP servers support the PORT command, try doing a transfer using
PASV instead!

31 FTP couldn't use REST. The REST command failed. This command is used for resumed FTP transfers.

33 HTTP range error. The range "command" didn't work.

34 HTTP post error. Internal post-request generation error.

35 SSL connect error. The SSL handshaking failed.

36 FTP bad download resume. Couldn't continue an earlier aborted download.

37 FILE couldn't read file. Failed to open the file. Permissions?

38 LDAP cannot bind. LDAP bind operation failed.

39 LDAP search failed.

41 Function not found. A required LDAP function was not found.

42 Aborted by callback. An application told curl to abort the operation.

43 Internal error. A function was called with a bad parameter.

45 Interface error. A specified outgoing interface could not be used.

47 Too many redirects. When following redirects, curl hit the maximum amount.

48 Unknown TELNET option specified.

49 Malformed telnet option.

51 The peer's SSL certificate or SSH MD5 fingerprint was not ok.

52 The server didn't reply anything, which here is considered an error.

53 SSL crypto engine not found.

54 Cannot set SSL crypto engine as default.

55 Failed sending network data.

56 Failure in receiving network data.

58 Problem with the local certificate.

59 Couldn't use specified SSL cipher.

60 Peer certificate cannot be authenticated with known CA certificates.

61 Unrecognized transfer encoding.

62 Invalid LDAP URL.

63 Maximum file size exceeded.

64 Requested FTP SSL level failed.

65 Sending the data requires a rewind that failed.

66 Failed to initialise SSL Engine.

67 The user name, password, or similar was not accepted and curl failed to log in.

68 File not found on TFTP server.

69 Permission problem on TFTP server.

70 Out of disk space on TFTP server.

71 Illegal TFTP operation.

72 Unknown TFTP transfer ID.

73 File already exists (TFTP).

74 No such user (TFTP).

75 Character conversion failed.

76 Character conversion functions required.

77 Problem with reading the SSL CA cert (path? access rights?).

78 The resource referenced in the URL does not exist.

79 An unspecified error occurred during the SSH session.

80 Failed to shut down the SSL connection.

82 Could not load CRL file, missing or wrong format (added in 7.19.0).

83 Issuer check failed (added in 7.19.0).

XX More 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.

WWW
http://curl.haxx.se

FTP
ftp://ftp.sunet.se/pub/www/utilities/curl/