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 (DICT, FILE, FTP, FTPS, GOPHER, HTTP, HTTPS, IMAP,
IMAPS, LDAP, LDAPS, POP3, POP3S, RTMP, RTSP, SCP, SFTP, SMTP, SMTPS,
TELNET and TFTP). The command is designed to work without user inter‐
action.
curl offers a busload of useful tricks like proxy support, user authen‐
tication, FTP upload, HTTP post, SSL connections, cookies, file trans‐
fer resume and more. As you will see below, the number of features will
make your head spin!
curl is powered by libcurl for all transfer-related features. See
libcurl(3) for details.
URL
The URL syntax is protocol-dependent. You'll find a detailed 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
Nested sequences are not supported, 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.
You can specify a step counter for the ranges to 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 do its best to use what you pass to it as a URL. It is not
trying to validate it as a syntactically correct URL by any means but
is instead very liberal with what it accepts.
Curl will attempt to re-use connections for multiple file transfers, so
that getting many files from the same server will not do multiple 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
the amount of transferred data, transfer speeds and estimated time
left, etc.
curl displays this data to the terminal by default, so if you invoke
curl to do an operation and it is about to write data to the terminal,
it disables the progress meter as otherwise it would mess up the output
mixing progress meter and response data.
If you want a progress meter for HTTP POST or PUT requests, you need to
redirect the response output to a file, using shell redirect (>), -o
[file] or similar.
It is not the same case for FTP upload as that operation does not spit
out any response data to the terminal.
If you prefer a progress "bar" instead of the regular meter, -# is your
friend.
OPTIONS
In general, all boolean options are enabled with --option and yet again
disabled with --no-option. That is, you use the exact same option name
but prefix it with "no-". However, in this list we mostly only list and
show the --option version of them. (This concept with --no options was
added in 7.19.0. Previously most options were toggled on/off on
repeated use of the same command line option.)
-#, --progress-bar
Make curl display progress as a simple progress bar instead of
the standard, more informational, meter.
-0, --http1.0
(HTTP) Forces curl to issue its requests using HTTP 1.0 instead
of using its internally preferred: HTTP 1.1.
-1, --tlsv1
(SSL) Forces curl to use TLS version 1 when negotiating with a
remote TLS server.
-2, --sslv2
(SSL) Forces curl to use SSL version 2 when negotiating with a
remote SSL server.
-3, --sslv3
(SSL) Forces curl to use SSL version 3 when negotiating with a
remote SSL server.
-4, --ipv4
If libcurl is capable of resolving an address to multiple IP
versions (which it is if it is IPv6-capable), this option tells
libcurl to resolve names to IPv4 addresses only.
-6, --ipv6
If libcurl is capable of resolving an address to multiple IP
versions (which it is if it is IPv6-capable), this option tells
libcurl to resolve names to IPv6 addresses only. default sta‐
tistics.
-a, --append
(FTP/SFTP) When used in an upload, this will tell curl to append
to the target file instead of overwriting it. If the file
doesn't exist, it will be created. Note that this flag is
ignored by some SSH servers (including OpenSSH).
-A, --user-agent <agent string>
(HTTP) Specify the User-Agent string to send to the HTTP server.
Some badly done CGIs fail if this field isn't set to
"Mozilla/4.0". To encode blanks in the string, surround the
string with single quote marks. This can also be set with the
-H, --header option of course.
If this option is set more than once, the last one will be the
one that's used.
--anyauth
(HTTP) Tells curl to figure out authentication method by itself,
and use the most secure one the remote site claims to support.
This is done by first doing a request and checking the response-
headers, thus possibly inducing an extra network round-trip.
This is used instead of setting a specific authentication
method, which you can do with --basic, --digest, --ntlm, and
--negotiate.
Note that using --anyauth is not recommended if you do uploads
from stdin, since it may require data to be sent twice and then
the client must be able to rewind. If the need should arise when
uploading from stdin, the upload operation will fail.
-b, --cookie <name=data>
(HTTP) Pass the data to the HTTP server as a cookie. It is 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 '=' symbol 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.
--basic
(HTTP) Tells curl to use HTTP Basic authentication. This is the
default and this option is usually pointless, unless you use it
to override a previously set option that sets a different
authentication method (such as --ntlm, --digest, or --negoti‐
ate).
-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.
This command line option will activate the cookie engine that
makes curl record and use cookies. Another way to activate it is
to use the -b, --cookie option.
If the cookie jar can't be created or written to, the whole curl
operation won't fail or even report an error clearly. Using -v
will get a warning displayed, but that is the only visible feed‐
back you get about this possibly lethal situation.
If this option is used several times, the last specified file
name will be used.
-C, --continue-at <offset>
Continue/Resume a previous file transfer at the given offset.
The given offset is the exact number of bytes that will be
skipped, counting from the beginning of the source file before
it is transferred to the destination. If used with uploads, the
FTP server command SIZE will not be used by curl.
Use "-C -" to tell curl to automatically find out where/how to
resume the transfer. It then uses the given output/input files
to figure that out.
If this option is used several times, the last one will be used.
--ciphers <list of ciphers>
(SSL) Specifies which ciphers to use in the connection. The list
of ciphers must specify valid ciphers. Read up on SSL cipher
list details on this URL:
http://www.openssl.org/docs/apps/ciphers.html
NSS ciphers are done differently than OpenSSL and GnuTLS. The
full list of NSS ciphers is in the NSSCipherSuite entry at this
URL: http://directory.fedora.redhat.com/docs/mod_nss.html#Direc‐
tives
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 save the uncompressed document. If this
option is used and the server sends an unsupported encoding,
curl will report an error.
--connect-timeout <seconds>
Maximum time in seconds that you allow the connection to the
server to take. This only limits the connection phase, once
curl has connected this option is of no more use. See also the
-m, --max-time option.
If this option is used several times, the last one will be used.
--create-dirs
When used in conjunction with the -o option, curl will create
the necessary local directory hierarchy as needed. This option
creates the dirs mentioned with the -o option, nothing else. If
the -o file name uses no dir or if the dirs it mentions already
exist, no dir will be created.
To create remote directories when using FTP or SFTP, try --ftp-
create-dirs.
--crlf (FTP) Convert LF to CRLF in upload. Useful for MVS (OS/390).
--crlfile <file>
(HTTPS/FTPS) Provide a file using PEM format with a Certificate
Revocation List that may specify peer certificates that are to
be considered revoked.
If this option is used several times, the last one will be used.
(Added in 7.19.7)
-d, --data <data>
(HTTP) Sends the specified data in a POST request to the HTTP
server, in the same way that a browser does when a user has
filled in an HTML form and presses the submit button. This will
cause curl to pass the data to the server using the content-type
application/x-www-form-urlencoded. Compare to -F, --form.
-d, --data is the same as --data-ascii. To post data purely
binary, you should instead use the --data-binary option. To URL-
encode the value of a form field you may use --data-urlencode.
If any of these options is used more than once on the same com‐
mand line, the data pieces specified will be merged together
with a separating &-symbol. Thus, using '-d name=daniel -d
skill=lousy' would generate a post chunk that looks like
'name=daniel&skill=lousy'.
If you start the data with the letter @, the rest should be a
file name to read the data from, or - if you want curl to read
the data from stdin. The contents of the file must already be
URL-encoded. Multiple files can also be specified. Posting data
from a file named 'foobar' would thus be done with --data @foo‐
bar.
-D, --dump-header <file>
Write the protocol headers to the specified file.
This option is handy to use when you want to store the headers
that a HTTP site sends to you. Cookies from the headers could
then be read in a second curl invocation by using the -b,
--cookie option! The -c, --cookie-jar option is however a better
way to store cookies.
When used in FTP, the FTP server response lines are considered
being "headers" and thus are saved there.
If this option is used several times, the last one will be used.
IP "--data-ascii <data>" See -d, --data.
--data-binary <data>
(HTTP) This posts data exactly as specified with no extra pro‐
cessing whatsoever.
If you start the data with the letter @, the rest should be a
filename. Data is posted in a similar manner as --data-ascii
does, except that newlines are preserved and conversions are
never done.
If this option is used several times, the ones following the
first will append data as described in -d, --data.
--data-urlencode <data>
(HTTP) This posts data, similar to the other --data options with
the exception that this performs URL-encoding. (Added in 7.18.0)
To be CGI-compliant, the <data> part should begin with a name
followed by a separator and a content specification. The <data>
part can be passed to curl using one of the following syntaxes:
content
This will make curl URL-encode the content and pass that
on. Just be careful so that the content doesn't contain
any = or @ symbols, as that will then make the syntax
match one of the other cases below!
=content
This will make curl URL-encode the content and pass that
on. The preceding = symbol is not included in the data.
name=content
This will make curl URL-encode the content part and pass
that on. Note that the name part is expected to be URL-
encoded already.
@filename
This will make curl load data from the given file
(including any newlines), URL-encode that data and pass
it on in the POST.
name@filename
This will make curl load data from the given file
(including any newlines), URL-encode that data and pass
it on in the POST. The name part gets an equal sign
appended, resulting in name=urlencoded-file-content. Note
that the name is expected to be URL-encoded already.
--delegation LEVEL
Set LEVEL to tell the server what it is allowed to delegate when
it comes to user credentials. Used with GSS/kerberos.
none Don't allow any delegation.
policy Delegates if and only if the OK-AS-DELEGATE flag is set
in the Kerberos service ticket, which is a matter of
realm policy.
always Unconditionally allow the server to delegate.
--digest
(HTTP) Enables HTTP Digest authentication. This is a 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, and may not work on all
servers, but they enable more functionality in a better way than
the traditional PORT command.
--eprt can be used to explicitly enable EPRT again and --no-eprt
is an alias for --disable-eprt.
Disabling EPRT only changes the active behavior. If you want to
switch to passive mode you need to not use -P, --ftp-port or
force it with --ftp-pasv.
--disable-epsv
(FTP) Tell curl to disable the use of the EPSV command when
doing passive FTP transfers. Curl will normally always first
attempt to use EPSV before PASV, but with this option, it will
not try using EPSV.
--epsv can be used to explicitly enable EPSV again and --no-epsv
is an alias for --disable-epsv.
Disabling EPSV only changes the passive behavior. If you want to
switch to active mode you need to use -P, --ftp-port.
-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.
-E, --cert <certificate[:password]>
(SSL) Tells curl to use the specified client certificate file
when getting a file with HTTPS, FTPS or another SSL-based proto‐
col. The certificate must be in PEM format. If the optional
password isn't specified, it will be queried for on the termi‐
nal. Note that this option assumes a "certificate" file that is
the private key and the private certificate concatenated! See
--cert and --key to specify them independently.
If curl is built against the NSS SSL library then this option
can tell curl the nickname of the certificate to use within the
NSS database defined by the environment variable SSL_DIR (or by
default /etc/pki/nssdb). If the NSS PEM PKCS#11 module (lib‐
nsspem.so) is available then PEM files may be loaded. If you
want to use a file from the current directory, please precede it
with "./" prefix, in order to avoid confusion with a nickname.
If this option is used several times, the last one will be used.
--engine <name>
Select the OpenSSL crypto engine to use for cipher operations.
Use --engine list to print a list of build-time supported
engines. Note that not all (or none) of the engines may be
available at run-time.
--environment
(RISC OS ONLY) Sets a range of environment variables, using the
names the -w option supports, to allow easier extraction of use‐
ful information after having run curl.
--egd-file <file>
(SSL) Specify the path name to the Entropy Gathering Daemon
socket. The socket is used to seed the random engine for SSL
connections. See also the --random-file option.
--cert-type <type>
(SSL) Tells curl what certificate type the provided certificate
is in. PEM, DER and ENG are recognized types. If not specified,
PEM is assumed.
If this option is used several times, the last one will be used.
--cacert <CA certificate>
(SSL) Tells curl to use the specified certificate file to verify
the peer. The file may contain multiple CA certificates. The
certificate(s) must be in PEM format. Normally curl is built to
use a default file for this, so this option is typically used to
alter that default file.
curl recognizes the environment variable named 'CURL_CA_BUNDLE'
if it is set, and uses the given path as a path to a CA cert
bundle. This option overrides that variable.
The windows version of curl will automatically look for a CA
certs file named ´curl-ca-bundle.crt´, either in the same direc‐
tory as curl.exe, or in the Current Working Directory, or in any
folder along your PATH.
If curl is built against the NSS SSL library then this option
tells curl the nickname of the CA certificate to use within the
NSS database defined by the environment variable SSL_DIR (or by
default /etc/pki/nssdb). If the NSS PEM PKCS#11 module (lib‐
nsspem.so) is available then PEM files may be loaded.
If this option is used several times, the last one will be used.
--capath <CA certificate directory>
(SSL) Tells curl to use the specified certificate directory to
verify the peer. Multiple paths can be provided by separating
them with ":" (e.g. "path1:path2:path3"). The certificates must
be in PEM format, and if curl is built against OpenSSL, the
directory must have been processed using the c_rehash utility
supplied with OpenSSL. Using --capath can allow OpenSSL-powered
curl to make SSL-connections much more efficiently than using
--cacert if the --cacert file contains many CA certificates.
If this option is set, the default capath value will be ignored,
and if it is used several times, the last one will be used.
-f, --fail
(HTTP) Fail silently (no output at all) on server errors. This
is mostly done 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 pre‐
vent curl from outputting that and return error 22.
This method is not fail-safe and there are occasions where non-
successful response codes will slip through, especially when
authentication is involved (response codes 401 and 407).
-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 RFC
2388. This enables uploading of binary files etc. To force the
'content' part to be a file, prefix the file name with an @
sign. To just get the content part from a file, prefix the file
name with the symbol <. The difference between @ and < is then
that @ makes a file get attached in the post as a file upload,
while the < makes a text field and just get the contents for
that text field from a file.
Example, to send your password file to the server, where '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 content from stdin instead of a file, use - as the file‐
name. 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 a 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.
--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-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-create-dirs
(FTP/SFTP) When an FTP or SFTP URL/operation uses a path that
doesn't currently exist on the server, the standard behavior of
curl is to fail. Using this option, curl will instead attempt to
create missing directories.
--ftp-method [method]
(FTP) Control what method curl should use to reach a file on a
FTP(S) server. The method argument should be one of the 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 RFC 1738 says it should be done.
This is the default but the slowest behavior.
nocwd curl does no CWD at all. curl will do SIZE, RETR, STOR
etc and give a full path to the server for all these 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'.
(Added in 7.15.1)
--ftp-pasv
(FTP) Use passive mode for the data connection. Passive is the
internal default behavior, but using this option can be used to
override a previous -P/-ftp-port option. (Added in 7.11.0)
If this option is used several times, the following occurrences
make no difference. Undoing an enforced passive really isn't
doable but you must then instead enforce the correct -P, --ftp-
port again.
Passive mode means that curl will try the EPSV command first and
then PASV, unless --disable-epsv is used.
--ftp-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.
--ftp-pret
(FTP) Tell curl to send a PRET command before PASV (and EPSV).
Certain FTP servers, mainly drftpd, require this non-standard
command for directory listings as well as up and downloads in
PASV mode. (Added in 7.20.x)
--ftp-ssl-ccc
(FTP) Use CCC (Clear Command Channel) Shuts down the SSL/TLS
layer after authenticating. The rest of the control channel com‐
munication will be unencrypted. This allows NAT routers to fol‐
low the FTP transaction. The default mode is passive. See --ftp-
ssl-ccc-mode for other modes. (Added in 7.16.1)
--ftp-ssl-ccc-mode [active/passive]
(FTP) Use CCC (Clear Command Channel) Sets the CCC mode. The
passive mode will not initiate the shutdown, but instead wait
for the server to do it, and will not reply to the shutdown from
the server. The active mode initiates the shutdown and waits for
a reply from the server. (Added in 7.16.2)
--ftp-ssl-control
(FTP) Require SSL/TLS for the FTP login, clear for transfer.
Allows secure authentication, but non-encrypted data transfers
for efficiency. Fails the transfer if the server doesn't sup‐
port SSL/TLS. (Added in 7.16.0) that can still be used but will
be removed in a future version.
--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. This is because undoing a GET doesn't make
sense, but you should then instead enforce the alternative
method you prefer.
-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. Remove an internal header by giving a replacement
without content on the right side of the colon, as in: -H
"Host:". If you send the custom header with no-value then its
header must be terminated with a semicolon, such as -H "X-Cus‐
tom-Header;" to send "X-Custom-Header:".
curl will make sure that each header you add/replace is sent
with the proper end-of-line marker, you should thus not add that
as a part of the header content: do not add newlines or carriage
returns, they will only mess things up for you.
See also the -A, --user-agent and -e, --referer options.
This option can be used multiple times to add/replace/remove
multiple headers.
--hostpubmd5 <md5>
Pass a string containing 32 hexadecimal digits. The string
should be the 128 bit MD5 checksum of the remote host's public
key, curl will refuse the connection with the host unless the
md5sums match. This option is only for SCP and SFTP transfers.
(Added in 7.17.1)
--ignore-content-length
(HTTP) Ignore the Content-Length header. This is particularly
useful for servers running Apache 1.x, which will report 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...
-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.
--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.
-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.
-J, --remote-header-name
(HTTP) This option tells the -O, --remote-name option to use the
server-specified Content-Disposition filename instead of
extracting a filename from the URL.
-k, --insecure
(SSL) This option explicitly allows curl to perform "insecure"
SSL connections and transfers. All SSL connections are attempted
to be made secure by using the CA certificate bundle installed
by default. This makes all connections considered "insecure"
fail unless -k, --insecure is used.
See this online resource for further details:
http://curl.haxx.se/docs/sslcerts.html
-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, separated by whitespace,
colon, the equals sign or any combination thereof (however, the
preferred separator is the equals sign). If the parameter is to
contain whitespace, the parameter must be enclosed within
quotes. Within double quotes, the following escape sequences are
available: \\, \", \t, \n, \r and \v. A backslash preceding any
other letter is ignored. If the first column of a config line is
a '#' character, the rest of the line will be treated as a com‐
ment. Only write one option per physical line in the config
file.
Specify the filename to -K, --config as '-' to make curl read
the file from stdin.
Note that to be able to specify a URL in the config file, you
need to specify it using the --url option, and not by simply
writing the URL on its own line. So, it could look similar to
this:
url = "http://curl.haxx.se/docs/"
Long option names can optionally be given in the config file
without the initial double dashes.
When curl is invoked, it always (unless -q is used) checks for a
default config file and uses it if found. The default config
file is checked for in the following places in this order:
1) curl tries to find the "home dir": It first checks for the
CURL_HOME and then the HOME environment variables. Failing that,
it uses getpwuid() on UNIX-like systems (which returns the home
dir given the current user in your system). On Windows, it then
checks for the APPDATA variable, or as a last resort the '%USER‐
PROFILE%\Application Data'.
2) On windows, if there is no _curlrc file in the home dir, it
checks for one in the same dir the curl executable is placed. On
UNIX-like systems, it will simply try to load .curlrc from the
determined home dir.
# --- Example file ---
# this is a comment
url = "curl.haxx.se"
output = "curlhere.html"
user-agent = "superagent/1.0"
# and fetch another URL too
url = "curl.haxx.se/docs/manpage.html"
-O
referer = "http://nowhereatall.com/"
# --- End of example file ---
This option can be used multiple times to load multiple config
files.
--keepalive-time <seconds>
This option sets the time a connection needs to remain idle
before sending keepalive probes and the time between individual
keepalive probes. It is currently effective on operating systems
offering the TCP_KEEPIDLE and TCP_KEEPINTVL socket options
(meaning Linux, recent AIX, HP-UX and more). This option has no
effect if --no-keepalive is used. (Added in 7.18.0)
If this option is used multiple times, the last occurrence sets
the amount. If unspecified, the option defaults to 60 seconds.
--key <key>
(SSL/SSH) Private key file name. Allows you to provide your pri‐
vate 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 not
specified, PEM is assumed.
If this option is used several times, the last one will be used.
--krb <level>
(FTP) Enable Kerberos authentication and use. The level must be
entered and should be one of 'clear', 'safe', 'confidential', or
'private'. Should you use a level that is not one of these,
'private' will instead be used.
This option requires a library built with kerberos4 or GSSAPI
(GSS-Negotiate) support. This is not very common. Use -V, --ver‐
sion to see if your curl supports it.
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.
-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.
When curl follows a redirect and the request is not a plain GET
(for example POST or PUT), it will do the following request with
a GET if the HTTP response was 301, 302, or 303. If the response
code was any other 3xx code, curl will re-send the following
request using the same unmodified method.
--libcurl <file>
Append this option to any ordinary curl command line, and you
will get a libcurl-using C source code written to the file that
does the equivalent of what your command-line operation does!
If this option is used several times, the last given file name
will be used. (Added in 7.16.1)
--limit-rate <speed>
Specify the maximum transfer rate you want curl to use. This
feature is useful if you have a limited pipe and you'd like your
transfer not to use your entire bandwidth.
The given speed is measured in bytes/second, unless a suffix is
appended. Appending 'k' or 'K' will count the number as kilo‐
bytes, 'm' or M' makes it megabytes, while 'g' or 'G' makes it
gigabytes. Examples: 200K, 3m and 1G.
The given rate is the average speed counted during the entire
transfer. It means that curl might use higher transfer speeds in
short bursts, but over time it uses no more than the given rate.
If you also use the -Y, --speed-limit option, that option will
take precedence and might cripple the rate-limiting slightly, to
help keeping the speed-limit logic working.
If this option is used several times, the last one will be used.
--local-port <num>[-num]
Set a preferred number or range of local port numbers to use for
the connection(s). Note that port numbers by nature are a
scarce resource that will be busy at times so setting this range
to something too narrow might cause unnecessary connection setup
failures. (Added in 7.15.2)
--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 to a site to which you'll send your authentication info
(which is plaintext in the case of HTTP Basic authentication).
-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.
--mail-auth <address>
(SMTP) Specify a single address. This will be used to specify
the authentication address (identity) of a submitted message
that is being relayed to another server.
(Added in 7.25.0)
--mail-from <address>
(SMTP) Specify a single address that the given mail should get
sent from.
(Added in 7.20.0)
--max-filesize <bytes>
Specify the maximum size (in bytes) of a file to download. If
the file requested is larger than this value, the transfer will
not start and curl will return with exit code 63.
NOTE: The file size is not always known prior to download, and
for such files this option has no effect even if the file trans‐
fer ends up being larger than this given limit. This concerns
both FTP and HTTP transfers.
--mail-rcpt <address>
(SMTP) Specify a single address that the given mail should get
sent to. This option can be used multiple times to specify many
recipients.
(Added in 7.20.0)
--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 limit‐
less.
If this option is used several times, the last one will be used.
-n, --netrc
Makes curl scan the .netrc (_netrc on Windows) file in the
user's home directory for login name and password. This is typi‐
cally used for FTP on UNIX. If used with HTTP, curl will enable
user authentication. See netrc(4) or ftp(1) for details on the
file format. Curl will not complain if that file doesn't have
the right permissions (it should not be either world- or group-
readable). The environment variable "HOME" is used to find the
home directory.
A quick and very simple example of how to setup a .netrc to
allow curl to FTP to the machine host.domain.com with user name
'myself' and password 'secret' should look similar to:
machine host.domain.com login myself password secret
-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.
Note that this is the negated option name documented. You can
thus use --buffer to enforce the buffering.
--netrc-file
This option is similar to --netrc, except that you provide the
path (absolute or relative) to the netrc file that Curl should
use. You can only specify one netrc file per invocation. If
several --netrc-file options are provided, only the last one
will be used. (Added in 7.21.5)
This option overrides any use of --netrc as they are mutually
exclusive. It will also abide by --netrc-optional if specified.
--netrc-optional
Very similar to --netrc, but this option makes the .netrc usage
optional and not mandatory as the --netrc option does.
--negotiate
(HTTP) Enables GSS-Negotiate authentication. The GSS-Negotiate
method was designed by Microsoft and is used in their web appli‐
cations. It is primarily meant as a support for Kerberos5
authentication but may be also used along with another authenti‐
cation method. For more information see IETF draft draft-brezak-
spnego-http-04.txt.
If you want to enable Negotiate for your proxy authentication,
then use --proxy-negotiate.
This option requires a library built with GSSAPI support. This
is not very common. Use -V, --version to see if your version
supports GSS-Negotiate.
When using this option, you must also provide a fake -u, --user
option to activate the authentication code 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.
--no-keepalive
Disables the use of keepalive messages on the TCP connection, as
by default curl enables them.
Note that this is the negated option name documented. You can
thus use --keepalive to enforce keepalive.
--no-sessionid
(SSL) Disable curl's use of SSL session-ID caching. By default
all transfers are done using the cache. Note that while nothing
should ever get hurt by attempting to reuse SSL session-IDs,
there seem to be broken SSL implementations in the wild that may
require you to disable this in order for you to succeed. (Added
in 7.16.0)
Note that this is the negated option name documented. You can
thus use --sessionid to enforce session-ID caching.
--noproxy <no-proxy-list>
Comma-separated list of hosts which do not use a proxy, if one
is specified. The only wildcard is a single * character, which
matches all hosts, and effectively disables the proxy. Each name
in this list is matched as either a domain which contains the
hostname, or the hostname itself. For example, local.com would
match local.com, local.com:80, and www.local.com, but not
www.notlocal.com. (Added in 7.19.4).
--ntlm (HTTP) Enables NTLM authentication. The NTLM authentication
method was designed by Microsoft and is used by IIS web servers.
It is a proprietary protocol, reverse-engineered by clever 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 a library built with SSL support. Use -V,
--version to see if your curl supports NTLM.
If this option is used several times, the following occurrences
make no difference.
-o, --output <file>
Write output to <file> instead of stdout. If you are using {} or
[] to fetch multiple documents, you can use '#' followed by a
number in the <file> specifier. That variable will be replaced
with the current string for the URL being fetched. Like in:
curl http://{one,two}.site.com -o "file_#1.txt"
or use several variables like:
curl http://{site,host}.host[1-5].com -o "#1_#2"
You may use this option as many times as the number of URLs you
have.
See also the --create-dirs option to create the local directo‐
ries dynamically. Specifying the output as '-' (a single dash)
will force the output to be done to stdout.
-O, --remote-name
Write output to a local file named like the remote file we get.
(Only the file part of the remote file is used, the path is cut
off.)
The remote file name to use for saving is extracted from the
given URL, nothing else.
Consequentially, the file will be saved in the current working
directory. If you want the file saved in a different directory,
make sure you change current working directory before you invoke
curl with the -O, --remote-name flag!
You may use this option as many times as the number of URLs you
have.
-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.
-P, --ftp-port <address>
(FTP) Reverses the default initiator/listener roles when con‐
necting with FTP. This switch makes curl use active mode. In
practice, curl then tells the server to connect back to the
client's specified address and port, while passive mode asks the
server to setup an IP address and port for it to connect to.
<address> should be one of:
interface
i.e "eth0" to specify which interface's IP address you
want to use (Unix only)
IP address
i.e "192.168.10.1" to specify the exact IP address
host name
i.e "my.host.domain" to specify the machine
- make curl pick the same IP address that is already used
for the control connection
If this option is used several times, the last one will be used. 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++.
Starting in 7.19.5, you can append ":[start]-[end]" to the right of the
address, to tell curl what TCP port range to use. That means you spec‐
ify a port range, from a lower to a higher number. A single number
works as well, but do note that it increases the risk of failure since
the port may not be available.
--pass <phrase>
(SSL/SSH) Passphrase for the private key
If this option is used several times, the last one will be used.
--post301
Tells curl to respect RFC 2616/10.3.2 and not convert POST
requests into GET requests when following a 301 redirection. The
non-RFC behaviour is ubiquitous in web browsers, so curl does
the conversion by default to maintain consistency. However, a
server may require a POST to remain a POST after such a redi‐
rection. This option is meaningful only when using -L, --loca‐
tion (Added in 7.17.1)
--post302
Tells curl to respect RFC 2616/10.3.2 and not convert POST
requests into GET requests when following a 302 redirection. The
non-RFC behaviour is ubiquitous in web browsers, so curl does
the conversion by default to maintain consistency. However, a
server may require a POST to remain a POST after such a redi‐
rection. This option is meaningful only when using -L, --loca‐
tion (Added in 7.19.1)
--proto <protocols>
Tells curl to use the listed protocols for its initial
retrieval. Protocols are evaluated left to right, are comma sep‐
arated, and are each a protocol name or 'all', optionally pre‐
fixed by zero or more modifiers. Available modifiers are:
+ Permit this protocol in addition to protocols already permit‐
ted (this is the default if no modifier is used).
- Deny this protocol, removing it from the list of protocols
already permitted.
= Permit only this protocol (ignoring the list already permit‐
ted), though subject to later modification by subsequent
entries in the comma separated list.
For example:
--proto -ftps uses the default protocols, but disables ftps
--proto -all,https,+http
only enables http and https
--proto =http,https
also only enables http and https
Unknown protocols produce a warning. This allows scripts to
safely rely on being able to disable potentially dangerous pro‐
tocols, without relying upon support for that protocol being
built into curl to avoid an error.
This option can be used multiple times, in which case the effect
is the same as concatenating the protocols into one instance of
the option.
(Added in 7.20.2)
--proto-redir <protocols>
Tells curl to use the listed protocols after a redirect. See
--proto for how protocols are represented.
(Added in 7.20.2)
--proxy-anyauth
Tells curl to pick a suitable authentication method when commu‐
nicating with the given proxy. This might cause an extra
request/response round-trip. (Added in 7.13.2)
--proxy-basic
Tells curl to use HTTP Basic authentication when communicating
with the given proxy. Use --basic for enabling HTTP Basic with a
remote host. Basic is the default authentication method curl
uses with proxies.
--proxy-digest
Tells curl to use HTTP Digest authentication when communicating
with the given proxy. Use --digest for enabling HTTP Digest with
a remote host.
--proxy-negotiate
Tells curl to use HTTP Negotiate authentication when communicat‐
ing with the given proxy. Use --negotiate for enabling HTTP
Negotiate with a remote host. (Added in 7.17.1)
--proxy-ntlm
Tells curl to use HTTP NTLM authentication when communicating
with the given proxy. Use --ntlm for enabling NTLM with a remote
host.
--proxy1.0 <proxyhost[:port]>
Use the specified HTTP 1.0 proxy. If the port number is not
specified, it is assumed at port 1080.
The only difference between this and the HTTP proxy option (-x,
--proxy), is that attempts to use CONNECT through the proxy will
specify an HTTP 1.0 protocol instead of the default HTTP 1.1.
--pubkey <key>
(SSH) Public key file name. Allows you to provide your public
key in this separate file.
If this option is used several times, the last one will be used.
-q If used as the first parameter on the command line, the curlrc
config file will not be read and used. See the -K, --config for
details on the default config file search path.
-Q, --quote <command>
(FTP/SFTP) Send an arbitrary command to the remote FTP or SFTP
server. Quote commands are sent BEFORE the transfer takes place
(just after the initial PWD command in an FTP transfer, to be
exact). To make commands take place after a successful transfer,
prefix them with a dash '-'. To make commands be sent after
libcurl has changed the working directory, just before the
transfer command(s), prefix the command with a '+' (this is only
supported for FTP). You may specify any number of commands. If
the server returns failure for one of the commands, the entire
operation will be aborted. You must send syntactically correct
FTP commands as RFC 959 defines to FTP servers, or one of the
commands listed below to SFTP servers. This option can be used
multiple times. When speaking to a FTP server, prefix the com‐
mand with an asterisk (*) to make libcurl continue even if the
command fails as by default curl will stop at first failure.
SFTP is a binary protocol. Unlike for FTP, libcurl interprets
SFTP quote commands itself before sending them to the server.
File names may be quoted shell-style to embed spaces or special
characters. Following is the list of all supported SFTP quote
commands:
chgrp group file
The chgrp command sets the group ID of the file named by
the file operand to the group ID specified by the group
operand. The group operand is a decimal integer group ID.
chmod mode file
The chmod command modifies the file mode bits of the
specified file. The mode operand is an octal integer mode
number.
chown user file
The chown command sets the owner of the file named by the
file operand to the user ID specified by the user oper‐
and. The user operand is a decimal integer user ID.
ln source_file target_file
The ln and symlink commands create a symbolic link at the
target_file location pointing to the source_file loca‐
tion.
mkdir directory_name
The mkdir command creates the directory named by the
directory_name operand.
pwd The pwd command returns the absolute pathname of the cur‐
rent working directory.
rename source target
The rename command renames the file or directory named by
the source operand to the destination path named by the
target operand.
rm file
The rm command removes the file specified by the file op‐
erand.
rmdir directory
The rmdir command removes the directory entry specified
by the directory operand, provided it is empty.
symlink source_file target_file
See ln.
-r, --range <range>
(HTTP/FTP/SFTP/FILE) Retrieve a byte range (i.e a partial docu‐
ment) from a HTTP/1.1, FTP or SFTP server or a local FILE.
Ranges can be specified in a number of ways.
0-499 specifies the first 500 bytes
500-999 specifies the second 500 bytes
-500 specifies the last 500 bytes
9500- specifies the bytes from offset 9500 and forward
0-0,-1 specifies the first and last byte only(*)(H)
500-700,600-799
specifies 300 bytes from offset 500(H)
100-199,500-599
specifies two separate 100-byte ranges(*)(H)
(*) = NOTE that this will cause the server to reply with a multipart
response!
Only digit characters (0-9) are valid in the 'start' and 'stop' fields
of the 'start-stop' range syntax. If a non-digit character is given in
the range, the server's response will be unspecified, depending on the
server's configuration.
You should also be aware that many HTTP/1.1 servers do not have this
feature enabled, so that when you attempt to get a range, you'll
instead get the whole document.
FTP and SFTP range downloads only support the simple 'start-stop' syn‐
tax (optionally with one of the numbers omitted). FTP use depends on
the extended FTP command SIZE.
If this option is used several times, the last one will be used.
-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.
--random-file <file>
(SSL) Specify the path name to file containing what will be con‐
sidered as random data. The data is used to seed the random
engine for SSL connections. See also the --egd-file option.
--raw When used, it disables all internal HTTP decoding of content or
transfer encodings and instead makes them passed on unaltered,
raw. (Added in 7.16.2)
--remote-name-all
This option changes the default action for all given URLs to be
dealt with as if -O, --remote-name were used for each one. So if
you want to disable that for a specific URL after --remote-name-
all has been used, you must use "-o -" or --no-remote-name.
(Added in 7.19.0)
--resolve <host:port:address>
Provide a custom address for a specific host and port pair.
Using this, you can make the curlrequests(s) use a specified
address and prevent the otherwise normally resolved address to
be used. Consider it a sort of /etc/hosts alternative provided
on the command line. The port number should be the number used
for the specific protocol the host will be used for. It means
you need several entries if you want to provide address for the
same host but different ports.
This option can be used many times to add many host names to
resolve.
(Added in 7.21.3)
--retry <num>
If a transient error is returned when curl tries to perform a
transfer, it will retry this number of times before giving up.
Setting the number to 0 makes curl do no retries (which is the
default). Transient error means either: a timeout, an FTP 4xx
response code or an HTTP 5xx response code.
When curl is about to retry a transfer, it will first wait one
second and then for all forthcoming retries it will double the
waiting time until it reaches 10 minutes which then will be the
delay between the rest of the retries. By using --retry-delay
you disable this exponential backoff algorithm. See also
--retry-max-time to limit the total time allowed for retries.
(Added in 7.12.3)
If this option is used multiple times, the last occurrence
decide the amount.
--retry-delay <seconds>
Make curl sleep this amount of time before each retry when a
transfer has failed with a transient error (it changes the
default backoff time algorithm between retries). This option is
only interesting if --retry is also used. Setting this delay to
zero will make curl use the default backoff time. (Added in
7.12.3)
If this option is used multiple times, the last occurrence
determines the amount.
--retry-max-time <seconds>
The retry timer is reset before the first transfer attempt.
Retries will be done as usual (see --retry) as long as the timer
hasn't reached this given limit. Notice that if the timer hasn't
reached the limit, the request will be made and while 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
determines the amount.
-s, --silent
Silent or quiet mode. Don't show progress meter or error mes‐
sages. Makes Curl mute.
-S, --show-error
When used with -s it makes curl show an error message if it
fails.
--ssl (FTP, POP3, IMAP, SMTP) Try to use SSL/TLS for the connection.
Reverts to a non-secure connection if the server doesn't support
SSL/TLS. See also --ftp-ssl-control and --ssl-reqd for differ‐
ent levels of encryption required. (Added in 7.20.0)
This option was formerly known as --ftp-ssl (Added in 7.11.0).
That option name can still be used but will be removed in a
future version.
--ssl-reqd
(FTP, POP3, IMAP, SMTP) Require SSL/TLS for the connection.
Terminates the connection if the server doesn't support SSL/TLS.
(Added in 7.20.0)
This option was formerly known as --ftp-ssl-reqd (added in
7.15.5). That option name can still be used but will be removed
in a future version.
--ssl-allow-beast
(SSL) This option tells curl to not work around a security flaw
in the SSL3 and TLS1.0 protocols known as BEAST. If this option
isn't used, the SSL layer may use work-arounds known to cause
interoperability problems with some older SSL implementations.
WARNING: this option loosens the SSL security, and by using this
flag you ask for exactly that. (Added in 7.25.0)
--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.
Since 7.21.7, this option is superfluous since you can specify a
socks4 proxy with -x, --proxy using a socks4:// protocol prefix.
If this option is used several times, the last one will be used.
--socks4a <host[:port]>
Use the specified SOCKS4a proxy. If the port number is not spec‐
ified, it is assumed at port 1080. (Added in 7.18.0)
This option overrides any previous use of -x, --proxy, as they
are mutually exclusive.
Since 7.21.7, this option is superfluous since you can specify a
socks4a proxy with -x, --proxy using a socks4a:// protocol pre‐
fix.
If this option is used several times, the last one will be used.
--socks5-hostname <host[:port]>
Use the specified SOCKS5 proxy (and let the proxy resolve the
host name). If the port number is not specified, it is assumed
at port 1080. (Added in 7.18.0)
This option overrides any previous use of -x, --proxy, as they
are mutually exclusive.
Since 7.21.7, this option is superfluous since you can specify a
socks5 hostname proxy with -x, --proxy using a socks5h:// proto‐
col prefix.
If this option is used several times, the last one will be used.
(This option was previously wrongly documented and used as
--socks without the number appended.)
--socks5 <host[:port]>
Use the specified SOCKS5 proxy - but resolve the host name
locally. If the port number is not specified, it is assumed at
port 1080.
This option overrides any previous use of -x, --proxy, as they
are mutually exclusive.
Since 7.21.7, this option is superfluous since you can specify a
socks5 proxy with -x, --proxy using a socks5:// protocol prefix.
If this option is used several times, the last one will be used.
(This option was previously wrongly documented and used as
--socks without the number appended.)
This option (as well as --socks4) does not work with IPV6, FTPS
or LDAP.
--socks5-gssapi-service <servicename>
The default service name for a socks server is rcmd/server-fqdn.
This option allows you to change it.
Examples: --socks5 proxy-name --socks5-gssapi-service sockd
would use sockd/proxy-name --socks5 proxy-name --socks5-gssapi-
service sockd/real-name would use sockd/real-name for cases
where the proxy-name does not match the principal name. (Added
in 7.19.4).
--socks5-gssapi-nec
As part of the gssapi negotiation a protection mode is negoti‐
ated. RFC 1961 says in section 4.3/4.4 it should be protected,
but the NEC reference implementation does not. The option
--socks5-gssapi-nec allows the unprotected exchange of the pro‐
tection mode negotiation. (Added in 7.19.4).
--stderr <file>
Redirect all writes to stderr to the specified file instead. If
the file name is a plain '-', it is instead written to stdout.
If this option is used several times, the last one will be used.
-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. Alternately, the file name "." (a single period)
may be specified instead of "-" to use stdin in non-blocking
mode to allow reading server output while stdin is being
uploaded.
You can specify one -T for each URL on the command line. Each -T
+ URL pair specifies what to upload and to where. curl also 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/
--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)
--tftp-blksize <value>
(TFTP) Set TFTP BLKSIZE option (must be >512). This is the block
size that curl will try to use when transferring data to or from
a TFTP server. By default 512 bytes will be used.
If this option is used several times, the last one will be used.
(Added in 7.20.0)
--tlsauthtype <authtype>
Set TLS authentication type. Currently, the only supported
option is "SRP", for TLS-SRP (RFC 5054). If --tlsuser and
--tlspassword are specified but --tlsauthtype is not, then this
option defaults to "SRP". (Added in 7.21.4)
--tlsuser <user>
Set username for use with the TLS authentication method speci‐
fied with --tlsauthtype. Requires that --tlspassword also be
set. (Added in 7.21.4)
--tlspassword <password>
Set password for use with the TLS authentication method speci‐
fied with --tlsauthtype. Requires that --tlsuser also be set.
(Added in 7.21.4)
--tr-encoding
(HTTP) Request a compressed Transfer-Encoding response using one
of the algorithms libcurl supports, and uncompress the data
while receiving it.
(Added in 7.21.6)
--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.
This option overrides previous uses of -v, --verbose or --trace-
ascii.
If this option is used several times, the last one will be used.
--trace-ascii <file>
Enables a full trace dump of all incoming and outgoing data,
including descriptive information, to the given 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.
This option overrides previous uses of -v, --verbose or --trace.
If this option is used several times, the last one will be used.
--trace-time
Prepends a time stamp to each trace or verbose line that curl
displays. (Added in 7.14.0)
-u, --user <user:password>
Specify the user name and password to use for server authentica‐
tion. Overrides -n, --netrc and --netrc-optional.
If you just give the user name (without entering a colon) curl
will prompt for a password.
If you use an SSPI-enabled curl binary and do NTLM authentica‐
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 the user name and password to use for proxy authentica‐
tion.
If you use an SSPI-enabled curl binary and do NTLM authentica‐
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 useful for
debugging. A line starting with '>' means "header data" sent by
curl, '<' means "header data" received by curl that is hidden in
normal cases, and a line starting with '*' means additional info
provided by curl.
Note that if you only want HTTP headers in the output, -i,
--include might be the option you're looking for.
If you think this option still doesn't give you enough details,
consider using --trace or --trace-ascii instead.
This option overrides previous uses of --trace-ascii or --trace.
Use -s, --silent to make curl quiet.
-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 as %{variable_name} and to output a
normal % you just write them as %%. You can output a newline by
using \n, a carriage return with \r and a tab space with \t.
NOTE: The %-symbol is a special symbol in the win32-environment,
where all occurrences of % must be doubled when using this
option.
The variables available at this point are:
url_effective The URL that was fetched last. This is most mean‐
ingful if you've told curl to follow location:
headers.
filename_effective
The ultimate filename that curl writes out to.
This is only meaningful if curl is told to write
to a file with the --remote-name or --output
option. It's most useful in combination with the
--remote-header-name option. (Added in 7.25.1)
http_code The numerical response code that was found in the
last retrieved HTTP(S) or FTP(s) transfer. In
7.18.2 the alias response_code was added to show
the same info.
http_connect The numerical code that was found in the last
response (from a proxy) to a curl CONNECT
request. (Added in 7.12.4)
time_total The total time, in seconds, that the full 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 TCP connect to the remote host (or
proxy) was completed.
time_appconnect
The time, in seconds, it took from the start
until the SSL/SSH/etc connect/handshake to the
remote host was completed. (Added in 7.19.0)
time_pretransfer
The time, in seconds, it took from the start
until the file transfer was just about to begin.
This includes all pre-transfer commands and 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 the 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 was just about to be trans‐
ferred. This includes time_pretransfer and also
the time the server needed to calculate the
result.
size_download The total amount of bytes that were downloaded.
size_upload The total amount of bytes that were uploaded.
size_header The total amount of bytes of the downloaded 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. Bytes per second.
speed_upload The average upload speed that curl measured for
the complete upload. Bytes per second.
content_type The Content-Type of the requested document, if
there was any.
num_connects Number of new connects made in the recent trans‐
fer. (Added in 7.12.3)
num_redirects Number of redirects that were followed in the
request. (Added in 7.12.3)
redirect_url When a HTTP request was made without -L to follow
redirects, this variable will show the actual URL
a redirect would take you to. (Added in 7.18.2)
ftp_entry_path The initial path libcurl ended up in when logging
on to the remote FTP server. (Added in 7.15.4)
ssl_verify_result
The result of the SSL peer certificate verifica‐
tion that was requested. 0 means the verification
was successful. (Added in 7.19.0)
If this option is used several times, the last one will be used.
-x, --proxy <[protocol://][user:password@]proxyhost[:port]>
Use the specified HTTP proxy. If the port number is not speci‐
fied, it is assumed at port 1080.
This option overrides existing environment variables that set
the proxy to use. If there's an environment variable setting a
proxy, you can set proxy to "" to override it.
All operations that are performed over a HTTP proxy will trans‐
parently be converted to HTTP. It means that certain protocol
specific operations might not be available. This is not the case
if you can tunnel through the proxy, as one with the -p, --prox‐
ytunnel option.
User and password that might be provided in the proxy string are
URL decoded by libcurl. This allows you to pass in special char‐
acters such as @ by using %40 or pass in a colon with %3a.
The proxy host can be specified the exact same way as the proxy
environment variables, including the protocol prefix (http://)
and the embedded user + password.
From 7.21.7, the proxy string may be specified with a proto‐
col:// prefix to specify alternative proxy protocols. Use
socks4://, socks4a://, socks5:// or socks5h:// to request the
specific SOCKS version to be used. No protocol specified,
http:// and all others will be treated as HTTP proxies.
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.
Common additional HTTP requests include PUT and DELETE, but
related technologies like WebDAV offers PROPFIND, COPY, MOVE and
more.
(FTP) Specifies a custom FTP command to use instead of LIST when
doing file lists with FTP.
If this option is used several times, the last one will be used.
--xattr
When saving output to a file, this option tells curl to store
certain file metadata in extened file attributes. Currently, the
URL is stored in the xdg.origin.url attribute and, for HTTP, the
content type is stored in the mime_type attribute. If the file
system does not support extended attributes, a warning is
issued.
-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>|<file>
(HTTP/FTP) Request a file that has been modified later than the
given time and date, or one that has been modified before that
time. The <date expression> can be all sorts of date strings or
if it doesn't match any internal ones, it is taken as a filename
and tries to get the modification date (mtime) from <file>
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.
-h, --help
Usage help.
-M, --manual
Manual. Display the huge help text.
-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 and krb5 for FTP is supported.
Debug This curl uses a libcurl built with Debug. This enables
more error-tracking and memory debugging etc. For curl-
developers only!
AsynchDNS
This curl uses asynchronous name resolves.
SPNEGO SPNEGO Negotiate authentication is supported.
Largefile
This curl supports transfers of large files, files larger
than 2GB.
IDN This curl supports IDN - international domain names.
SSPI SSPI is supported. If you use NTLM and set a blank user
name, curl will authenticate with your current user and
password.
TLS-SRP
SRP (Secure Remote Password) authentication is supported
for TLS.
FILES
~/.curlrc
Default config file, see -K, --config for details.
ENVIRONMENT
The environment variables can be specified in lower case or upper case.
The lower case version has precedence. http_proxy is an exception as it
is only available in lower case.
Using an environment variable to set the proxy has the same effect as
using the --proxy option.
http_proxy [protocol://]<host>[:port]
Sets the proxy server to use for HTTP.
HTTPS_PROXY [protocol://]<host>[:port]
Sets the proxy server to use for HTTPS.
[url-protocol]_PROXY [protocol://]<host>[:port]
Sets the proxy server to use for [url-protocol], where the pro‐
tocol is a protocol that curl supports and as specified in a
URL. FTP, FTPS, POP3, IMAP, SMTP, LDAP etc.
ALL_PROXY [protocol://]<host>[:port]
Sets the proxy server to use if no protocol-specific proxy is
set.
NO_PROXY <comma-separated list of hosts>
list of host names that shouldn't go through any proxy. If set
to a asterisk '*' only, it matches all hosts.
PROXY PROTOCOL PREFIXES
Since curl version 7.21.7, the proxy string may be specified with a
protocol:// prefix to specify alternative proxy protocols.
If no protocol is specified in the proxy string or if the string
doesn't match a supported one, the proxy will be treated as a HTTP
proxy.
The supported proxy protocol prefixes are as follows:
socks4://
Makes it the equivalent of --socks4
socks4a://
Makes it the equivalent of --socks4a
socks5://
Makes it the equivalent of --socks5
socks5h://
Makes it the equivalent of --socks5-hostname
EXIT CODES
There are a bunch of different error codes and their corresponding
error messages that may appear during bad conditions. At the time of
this writing, the exit codes are:
1 Unsupported protocol. This build of curl has no support for this
protocol.
2 Failed to initialize.
3 URL malformed. The syntax was not correct.
4 A feature or option that was needed to perform the desired
request was not enabled or was explicitly disabled at build-
time. To make curl able to do this, you probably need another
build of libcurl!
5 Couldn't resolve proxy. The given proxy host could not be
resolved.
6 Couldn't resolve host. The given remote host was not resolved.
7 Failed to connect to host.
8 FTP weird server reply. The server sent data curl couldn't
parse.
9 FTP access denied. The server denied login or denied access to
the particular resource or directory you wanted to reach. Most
often you tried to change to a directory that doesn't exist on
the server.
11 FTP weird PASS reply. Curl couldn't parse the reply sent to the
PASS request.
13 FTP weird PASV reply, Curl couldn't parse the reply sent to the
PASV request.
14 FTP weird 227 format. Curl couldn't parse the 227-line the
server sent.
15 FTP can't get host. Couldn't resolve the host IP we got in the
227-line.
17 FTP couldn't set binary. Couldn't change transfer method to
binary.
18 Partial file. Only a part of the file was transferred.
19 FTP couldn't download/access the given file, the RETR (or simi‐
lar) command failed.
21 FTP quote error. A quote command returned error from the server.
22 HTTP page not retrieved. The requested url was not found or
returned another error with the HTTP error code being 400 or
above. This return code only appears if -f, --fail is used.
23 Write error. Curl couldn't write data to a local filesystem or
similar.
25 FTP couldn't STOR file. The server denied the STOR operation,
used for FTP uploading.
26 Read error. Various reading problems.
27 Out of memory. A memory allocation request failed.
28 Operation timeout. The specified time-out period was reached
according to the conditions.
30 FTP PORT failed. The PORT command failed. Not all FTP servers
support the PORT command, try doing a transfer using PASV
instead!
31 FTP couldn't use REST. The REST command failed. This command is
used for resumed FTP transfers.
33 HTTP range error. The range "command" didn't work.
34 HTTP post error. Internal post-request generation error.
35 SSL connect error. The SSL handshaking failed.
36 FTP bad download resume. Couldn't continue an earlier aborted
download.
37 FILE couldn't read file. Failed to open the file. Permissions?
38 LDAP cannot bind. LDAP bind operation failed.
39 LDAP search failed.
41 Function not found. A required LDAP function was not found.
42 Aborted by callback. An application told curl to abort the oper‐
ation.
43 Internal error. A function was called with a bad parameter.
45 Interface error. A specified outgoing interface could not be
used.
47 Too many redirects. When following redirects, curl hit the maxi‐
mum amount.
48 Unknown option specified to libcurl. This indicates that you
passed a weird option to curl that was passed on to libcurl and
rejected. Read up in the manual!
49 Malformed telnet option.
51 The peer's SSL certificate or SSH MD5 fingerprint was not OK.
52 The server didn't reply anything, which here is considered an
error.
53 SSL crypto engine not found.
54 Cannot set SSL crypto engine as default.
55 Failed sending network data.
56 Failure in receiving network data.
58 Problem with the local certificate.
59 Couldn't use specified SSL cipher.
60 Peer certificate cannot be authenticated with known CA certifi‐
cates.
61 Unrecognized transfer encoding.
62 Invalid LDAP URL.
63 Maximum file size exceeded.
64 Requested FTP SSL level failed.
65 Sending the data requires a rewind that failed.
66 Failed to initialise SSL Engine.
67 The user name, password, or similar was not accepted and curl
failed to log in.
68 File not found on TFTP server.
69 Permission problem on TFTP server.
70 Out of disk space on TFTP server.
71 Illegal TFTP operation.
72 Unknown TFTP transfer ID.
73 File already exists (TFTP).
74 No such user (TFTP).
75 Character conversion failed.
76 Character conversion functions required.
77 Problem with reading the SSL CA cert (path? access rights?).
78 The resource referenced in the URL does not exist.
79 An unspecified error occurred during the SSH session.
80 Failed to shut down the SSL connection.
82 Could not load CRL file, missing or wrong format (added in
7.19.0).
83 Issuer check failed (added in 7.19.0).
84 The FTP PRET command failed
85 RTSP: mismatch of CSeq numbers
86 RTSP: mismatch of Session Identifiers
87 unable to parse FTP file list
88 FTP chunk callback reported error
XX More error codes will appear here in future releases. The exist‐
ing 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 7.25.0 16 February 2012 curl(1)
