curl(1) Curl Manual curl(1)NAMEcurl - transfer a URL
SYNOPSIScurl [options] [URL...]
DESCRIPTIONcurl is a tool to transfer data from or to a server, using one of the
supported protocols (HTTP, HTTPS, FTP, FTPS, 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 authen‐
tication, 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
libcurl(3) for details.
URL
The URL syntax is protocol dependent. You'll find a detailed descrip‐
tion 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 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 exam‐
ple, 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 con‐
nects / 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 METERcurl normally displays a progress meter during operations, indicating
amount of transfered data, transfer speeds and estimated time left etc.
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 spit‐
ting out any response data to the terminal.
If you prefer a progress "bar" instead of the regular meter, -# is your
friend.
OPTIONS
-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 sup‐
posedly 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 file‐
name 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 --negoti‐
ate).
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:
http://www.openssl.org/docs/apps/ciphers.html
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 tog‐
gle 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 writ‐
ten. 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 @foo‐
bar".
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 authentica‐
tion 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, --negoti‐
ate 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 exten‐
sions to the original FTP protocol, may not work on all servers
but enable more functionality in a better way than the tradi‐
tional PORT command.
If this option is used several times, each occurrence will tog‐
gle 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 tog‐
gle 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 fol‐
lows 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 use‐
ful information after having run curl.
If this option is used several times, each occurrence will tog‐
gle 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 for‐
mat. 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 ver‐
ify 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 direc‐
tory 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 pre‐
vious use.
--ftp-create-dirs
(FTP) When an FTP URL/operation uses a path that doesn't cur‐
rently 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 follow‐
ing 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 com‐
mands. 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 previ‐
ous --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 'con‐
tent' 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 'pass‐
word' 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 '<' charac‐
ters, and the ';type=' string in the value have no special mean‐
ing. 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 trick‐
ier 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 con‐
tent 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 incor‐
rect 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 tog‐
gle 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 pro‐
vided 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 con‐
fig 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 speci‐
fied on the same config file line. If the parameter is to con‐
tain 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 '%USER‐
PROFILE%0lication 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 kilo‐
bytes, '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 --loca‐
tion-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 trans‐
fer 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 hang‐
ing 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 appli‐
cations. It is primarily meant as a support for Kerberos5
authentication but may be also used along with another authenti‐
cation methods. For more information see IETF draft draft-
brezak-spnego-http-04.txt.
This option requires that the library was built with GSSAPI sup‐
port. 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 sit‐
uations, 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 peo‐
ple 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 authentica‐
tion 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 sup‐
port. 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 directo‐
ries 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 commu‐
nicating 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 tun‐
nel 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. Dis‐
able 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 com‐
mand with '+'. You may specify any amount of commands. If the
server returns failure for one of the commands, the entire oper‐
ation 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 perform‐
ing, 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 speci‐
fied, 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 speci‐
fied, 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 curl_easy_setopt(3) 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 sup‐
ports "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 tog‐
gle 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 autentica‐
tion, 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 autentica‐
tion, 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 ver‐
bose.
-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 success‐
ful operation. The format is a string that may contain plain
text mixed with any number of variables. The string can be spec‐
ified as "string", to get read from a particular file you spec‐
ify 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 loca‐
tion: 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 opera‐
tion 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 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 nego‐
tiations that are specific to the particular pro‐
tocol(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 execu‐
tion 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 trans‐
ferred. 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 head‐
ers.
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 trans‐
fer. (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 communicat‐
ing 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 sec‐
ond, 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 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 lim‐
itless.
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.
FILES
~/.curlrc
Default config file, see -K/--config for details.
ENVIRONMENT
http_proxy [protocol://]<host>[:port]
Sets proxy server to use for HTTP.
HTTPS_PROXY [protocol://]<host>[:port]
Sets proxy server to use for HTTPS.
FTP_PROXY [protocol://]<host>[:port]
Sets proxy server to use for FTP.
ALL_PROXY [protocol://]<host>[:port]
Sets 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 exists 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 malformat. The syntax was not correct.
4 URL user malformatted. The user-part of the URL 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.
10 FTP user/password incorrect. Either one or both were not
accepted by the server.
11 FTP weird PASS reply. Curl couldn't parse the reply sent to the
PASS request.
12 FTP weird USER reply. Curl couldn't parse the reply sent to the
USER 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.
16 FTP can't reconnect. Couldn't connect to the host 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 simi‐
lar) command failed.
20 FTP write error. The transfer was reported bad by the server.
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.
24 Malformed user. User name badly specified.
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.
29 FTP couldn't set ASCII. The server returned an unknown reply.
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.
32 FTP couldn't use SIZE. The SIZE command failed. The command is
an extension to the original FTP spec RFC 959.
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.
40 Library not found. The LDAP library was not found.
41 Function not found. A required LDAP function was not found.
42 Aborted by callback. An application told curl to abort the oper‐
ation.
43 Internal error. A function was called with a bad parameter.
44 Internal error. A function was called in a bad order.
45 Interface error. A specified outgoing interface could not be
used.
46 Bad password entered. An error was signaled when the password
was entered.
47 Too many redirects. When following redirects, curl hit the maxi‐
mum amount.
48 Unknown TELNET option specified.
49 Malformed telnet option.
51 The remote peer's SSL certificate wasn't 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
57 Share is in use (internal error)
58 Problem with the local certificate
59 Couldn't use specified SSL cipher
60 Problem with the CA cert (path? permission?)
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 User, password or similar was not accepted and curl failed to
login
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
XX There will appear more error codes 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/
SEE ALSOftp(1), wget(1)Curl 7.15.4 21 Mar 2006 curl(1)
