curl offers a busload of useful tricks like proxy support, user
authentication, ftp upload, HTTP post, SSL (https:) connections,
cookies, file transfer resume and more. As you will see below, the
amount of features will make your head spin!
curl is powered by libcurl for all transfer-related features.
See (3)
for details.
You can specify multiple URLs or parts of URLs by writing part
sets within braces 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:
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 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 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.
However, since curl displays 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 is not
spitting out any response data to the terminal.
- -a/--append
- (FTP) When used in an FTP 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.
If this option is used twice, the second one will disable append
mode again.
- -A/--user-agent <agent string>
- (HTTP) Specify the User-Agent string to send to the HTTP
server. Some badly done CGIs fail if its not 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 it
supports. This is done by first doing a request and checking the
response-headers, thus 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.
If this option is used several times, the following occurrences
make no difference.
- -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 '=' letter 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.
If this option is used twice, the second one will disable ASCII
usage.
- --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 and
--negotiate).
If this option is used several times, the following occurrences
make no difference.
- --ciphers <list of ciphers>
- (SSL) Specifies which ciphers to use in the connection. The
list of ciphers must be using valid ciphers. Read up on SSL cipher
list details on this URL:
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.
If this option is used several times, each occurrence will
toggle it on/off.
- --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 previously 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
counted 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.
- --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, try
--ftp-create-dirs.
- --crlf
- (FTP) Convert LF to CRLF in upload. Useful for MVS (OS/390).
If this option is used several times, the following occurrences
make no difference.
- -d/--data <data>
- (HTTP) Sends the specified data in a POST request to the HTTP
server, in a way that can emulate as if a user has filled in a HTML
form and pressed the submit button. Note that the data is sent
exactly as specified with no extra processing (with all newlines
cut off). The data is expected to be "url-encoded". This will cause
curl to pass the data to the server using the content-type
application/x-www-form-urlencoded. Compare to -F/--form. If
this option is used more than once on the same command line, the
data pieces specified will be merged together with a separating
&-letter. 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".
To post data purely binary, you should instead use the
--data-binary option.
-d/--data is the same as --data-ascii.
If this option is used several times, the ones following the
first will append data.
- --data-ascii <data>
- (HTTP) This is an alias for the -d/--data option.
If this option is used several times, the ones following the
first will append data.
- --data-binary <data>
- (HTTP) This posts data in a similar manner as
--data-ascii does, although when using this option the
entire context of the posted data is kept as-is. If you want to
post a binary file without the strip-newlines feature of the
--data-ascii option, this is for you.
If this option is used several times, the ones following the
first will append data.
- --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 password. 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 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, may not work on all
servers but enable more functionality in a better way than the
traditional PORT command.
If this option is used several times, each occurrence will
toggle this on/off.
- --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.
If this option is used several times, each occurrence will
toggle this on/off.
- -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 invoke by using the -b/--cookie
option! The -c/--cookie-jar option is however a better way
to store cookies.
When used on 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 easier allow extraction of useful
information after having run curl.
If this option is used several times, each occurrence will
toggle this on/off.
- --egd-file <file>
- (HTTPS) 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]>
- (HTTPS) Tells curl to use the specified certificate file when
getting a file with HTTPS. 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 certificate is the private key and the
private certificate concatenated!
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 this option is used several times, the last one will be used.
- --cacert <CA certificate>
- (HTTPS) 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.
curl recognizes the environment variable named 'CURL_CA_BUNDLE'
if that 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 this option is used several times, the last one will be used.
- --capath <CA certificate directory>
- (HTTPS) 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 --capath can allow curl to make
https 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 like this to better enable scripts etc to better
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.
If this option is used twice, the second will again disable
silent failure.
- --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) When an FTP 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.
If this option is used twice, the second will again disable
directory creation.
- --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 multicwd case). This
is somewhat more standards compliant than 'nocwd' but without the
full penalty of 'multicwd'.
- --ftp-pasv
- (FTP) Use PASV when transferring. PASV is the internal default
behavior, but using this option can be used to override a previous
--ftp-port option. (Added in 7.11.0)
If this option is used several times, the following occurrences
make no difference.
- --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 connection. (Added in 7.14.2)
This option has no effect if PORT, EPRT or EPSV is used instead
of PASV.
If this option is used twice, the second will again use the
server's suggested address.
- --ftp-ssl
- (FTP) Try to use SSL/TLS for the FTP connection. Reverts to a
non-secure connection if the server doesn't support SSL/TLS. (Added
in 7.11.0)
If this option is used twice, the second will again disable
this.
- --ftp-ssl-reqd
- (FTP) Require SSL/TLS for the FTP connection. Terminates the
connection if the server doesn't support SSL/TLS. (Added in 7.15.5)
If this option is used twice, the second will again disable
this.
- -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 RFC1867. 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 letter
<. 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
or
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.
- -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 normally do. You should not replace internally set
headers without knowing perfectly well what you're doing. Replacing
an internal header with one without content on the right side of
the colon will prevent that header from appearing.
curl will make sure that each header you add/replace get 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.
- --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 document,
HTTP-version and more...
If this option is used twice, the second will again disable
header include.
- --interface <name>
- 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 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.
If this option is used twice, the second will again disable
header 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 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.
If this option is used several times, each occurrence will
toggle this on/off.
- -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 connections considered "insecure" to fail
unless -k/--insecure is used.
If this option is used twice, the second time will again disable
it.
- --key <key>
- (SSL) 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
supported.
If this option is used several times, the last one will be used.
- --krb4 <level>
- (FTP) Enable kerberos4 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 that the library was built with kerberos4
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 arguments 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. If the parameter is to contain white
spaces, the parameter must be enclosed within quotes. If the first
column of a config line is a '#' character, the rest of the line
will be treated as a comment.
Specify the filename 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/"
This option can be used multiple times.
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 executable curl is placed. On
unix-like systems, it will simply try to load .curlrc from the
determined home dir.
- --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 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.
If you are also using 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 format.
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.
If this option is used twice, the second will again disable list
only.
- --local-port <num>[-num]
- Set a prefered number or range of local port numbers to use for
the connection(s). Note that port numbers by nature is 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.
If this option is used twice, the second will again disable
location following.
- --location-trusted
- (HTTP/HTTPS) 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 do a site to which you'll send your authentication
info (which is plaintext in the case of HTTP Basic authentication).
If this option is used twice, the second will again disable
location following.
- --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 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
hasn't the right permissions (it should not be world nor 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
If this option is used twice, the second will again disable
netrc usage.
- --netrc-optional
- Very similar to --netrc, but this option makes the
.netrc usage optional and not mandatory as the
--netrc 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 methods. For more information see IETF draft
draft-brezak-spnego-http-04.txt.
This option requires that the library was 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 properly. 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.
If this option is used twice, the second will again switch on
buffering.
- --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, reversed 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 that the library was 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 you have number of
URLs.
See also the --create-dirs option to create the local
directories dynamically.
- -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 you have number of
URLs.
- --pass <phrase>
- (SSL) Pass phrase for the private key
If this option is used several times, the last one will be used.
- --proxy-anyauth
- Tells curl to pick a suitable authentication method when
communicating with the given proxy. This will cause an extra
request/response round-trip. (Added in 7.13.2)
If this option is used twice, the second will again disable the
proxy use-any authentication.
- --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.
If this option is used twice, the second will again disable
proxy HTTP Basic authentication.
- --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.
If this option is used twice, the second will again disable
proxy HTTP Digest.
- --proxy-ntlm
- Tells curl to use HTTP NTLM authentication when communicating
with the given proxy. Use --ntlm for enabling NTLM with a
remote host.
If this option is used twice, the second will again disable
proxy HTTP NTLM.
- -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.
If this option is used twice, the second will again disable
proxy tunnel.
- -P/--ftp-port <address>
- (FTP) Reverses the initiator/listener roles when connecting
with ftp. This switch makes Curl use the PORT command instead of
PASV. In practice, PORT tells the server to connect to the client's
specified address and port, while PASV asks the server for an ip
address and port 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 exact IP number
- host name
- i.e "my.host.domain" to specify 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++.
- -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) Send an arbitrary command to the remote FTP server. Quote
commands are sent BEFORE the transfer is taking place (just after
the initial PWD command to be exact). To make commands take place
after a successful transfer, prefix them with a dash '-'. To make
commands get sent after libcurl has changed working directory, just
before the transfer command(s), prefix the command with '+'. You
may specify any amount 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.
This option can be used multiple times.
- --random-file <file>
- (HTTPS) 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) Retrieve a byte range (i.e a partial document) from
a HTTP/1.1 or FTP server. 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 bytes ranges(*)(H)
(*) = NOTE that this will cause the server to reply with a
multipart response!
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 range downloads only support the simple syntax 'start-stop'
(optionally with one of the numbers omitted). It depends on the
non-RFC command SIZE.
If this option is used several times, the last one will be used.
- -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.
If this option is used twice, the second time disables this
again.
- --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 5xx
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 between 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
decide 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
decide the amount.
- -s/--silent
- Silent mode. Don't show progress meter or error messages. Makes
Curl mute.
If this option is used twice, the second will again disable
silent mode.
- -S/--show-error
- When used with -s it makes curl show error message if it fails.
If this option is used twice, the second will again disable show
error.
- --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.
- --socks5 <host[:port]>
- Use the specified SOCKS5 proxy. If the port number is not
specified, it is assumed at port 1080. (Added in 7.11.1)
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.)
- --stderr <file>
- Redirect all writes to stderr to the specified file instead. If
the file name is a plain '-', it is instead written 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
man page for details about this option. (Added in 7.11.2)
If this option is used several times, each occurrence toggles
this on/off.
- -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.
- -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.
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 output file. Use
"-" as filename to have the output sent to stdout.
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 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.
- --trace-time
- Prepends a time stamp to each trace or verbose line that curl
displays. (Added in 7.14.0)
If this option is used several times, each occurrence will
toggle it on/off.
- -u/--user <user:password>
- Specify user and password to use for server authentication.
Overrides -n/--netrc and --netrc-optional.
If you use an SSPI-enabled curl binary and do NTLM
autentication, 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 user and password to use for proxy authentication.
If you use an SSPI-enabled curl binary and do NTLM
autentication, 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.
- --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 usable for
debugging. Lines starting with '>' means "header data" sent by
curl, '<' means "header data" received by curl that is hidden in
normal cases and lines starting with '*' means additional info
provided by curl.
Note that if you only want HTTP headers in the output,
-i/--include might be option you're looking for.
If you think this option still doesn't give you enough details,
consider using --trace or --trace-ascii instead.
If this option is used twice, the second will again disable
verbose.
- -V/--version
- Displays information about curl and the libcurl version it
uses.
The first line includes the full version of curl, libcurl and
other 3rd party libraries linked with the executable.
The second line (starts with "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 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 contain 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 like %{variable_name} and to output a
normal % you just write them like %%. You can output a newline by
using \n, a carriage return with \r and a tab space with \t.
NOTE: The %-letter is a special letter in the
win32-environment, where all occurrences of % must be doubled when
using this option.
Available variables are at this point:
-
- url_effective
- The URL that was fetched last. This is mostly meaningful if
you've told curl to follow location: headers.
- http_code
- The numerical code that was found in the last retrieved HTTP(S)
page.
- 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 millisecond 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 connect
to the remote host (or proxy) was completed.
- time_pretransfer
- The time, in seconds, it took from the start until the file
transfer is 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 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 is just about to be transferred. This includes
time_pretransfer and also the time the server needs 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.
- speed_upload
- The average upload speed that curl measured for the complete
upload.
- 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)
- ftp_entry_path
- The initial path libcurl ended up in when logging on to the
remote FTP server. (Added in 7.15.4)
If this option is used several times, the last one will be used.
- -x/--proxy <proxyhost[:port]>
- Use specified HTTP proxy. If the port number is not specified,
it is assumed at port 1080.
This option overrides existing environment variables that sets
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, include protocol
prefix (http://) and 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.
(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) 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
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
- (HTTPS) Forces curl to use TSL version 1 when negotiating with
a remote TLS server.
- -2/--sslv2
- (HTTPS) Forces curl to use SSL version 2 when negotiating with
a remote SSL server.
- -3/--sslv3
- (HTTPS) Forces curl to use SSL version 3 when negotiating with
a remote SSL server.
- --3p-quote
- (FTP) Specify arbitrary commands to send to the source server.
See the -Q/--quote option for details. (Added in 7.13.0)
- --3p-url
- (FTP) Activates a FTP 3rd party transfer. Specifies the source
URL to get a file from, while the "normal" URL will be used as
target URL, the file that will be written/created.
Note that not all FTP server allow 3rd party transfers. (Added
in 7.13.0)
- --3p-user
- (FTP) Specify user:password for the source URL transfer. (Added
in 7.13.0)
- -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.
If this option is used twice, the second will again disable the
progress bar.