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MAN page from StartCom 5 curl-7.15.5-2.1.SEL5_3.5.x86_64.rpm

curl

Section: Curl Manual (1)
Updated: 21 Mar 2006
Index 

NAME

curl - transfer a URL 

SYNOPSIS

curl [options][URL...] 

DESCRIPTION

curlis a tool to transfer data from or to a server, using one of the supportedprotocols (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, userauthentication, ftp upload, HTTP post, SSL (https:) connections, cookies, filetransfer resume and more. As you will see below, the amount of features willmake your head spin!

curl is powered by libcurl for all transfer-related features. Seelibcurl(3)for details. 

URL

The URL syntax is protocol dependent. You'll find a detailed description inRFC 3986.

You can specify multiple URLs or parts of URLs by writing part sets withinbraces 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 useseveral 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 fetchedin a sequential manner in the specified order.

Since curl 7.15.1 you can also specify step counter for the ranges, so thatyou 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 whatprotocol you might want. It will then default to HTTP but try other protocolsbased on often-used host name prefixes. For example, for host names startingwith "ftp." curl will assume you want to speak FTP.

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

PROGRESS METER

curl normally displays a progress meter during operations, indicating amountof transfered data, transfer speeds and estimated time left etc.

However, since curl displays data to the terminal by default, if you invokecurl to do an operation and it is about to write data to the terminal, itdisables the progress meter as otherwise it would mess up the outputmixing progress meter and response data.

If you want a progress meter for HTTP POST or PUT requests, you need toredirect the response output to a file, using shell redirect (>), -o [file] orsimilar.

It is not the same case for FTP upload as that operation is not spitting outany response data to the terminal.

If you prefer a progress "bar" instead of the regular meter, -# is yourfriend. 

OPTIONS

-a/--append
(FTP) When used in an FTP upload, this will tell curl to append to the targetfile 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 badlydone CGIs fail if its not set to "Mozilla/4.0". To encode blanks in thestring, surround the string with single quote marks. This can also be setwith the -H/--header option of course.

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

--anyauth
(HTTP) Tells curl to figure out authentication method by itself, and use themost secure one the remote site claims it supports. This is done by firstdoing a request and checking the response-headers, thus inducing an extranetwork round-trip. This is used instead of setting a specific authenticationmethod, 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 torewind. If the need should arise when uploading from stdin, the uploadoperation will fail.

If this option is used several times, the following occurrences make nodifference.

-b/--cookie <name=data>
(HTTP)Pass the data to the HTTP server as a cookie. It is supposedly thedata previously received from the server in a "Set-Cookie:" line.The data should be in the format "NAME1=VALUE1; NAME2=VALUE2".

If no '=' letter is used in the line, it is treated as a filename to use toread previously stored cookie lines from, which should be used in this sessionif they match. Using this method also activates the "cookie parser" which willmake curl record incoming cookies too, which may be handy if you're using thisin combination with the -L/--location option. The file format of thefile to read cookies from should be plain HTTP headers or the Netscape/Mozillacookie file format.

NOTE that the file specified with -b/--cookie is only used asinput. 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 fileusing -D/--dump-header!

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

-B/--use-ascii
Enable ASCII transfer when using FTP or LDAP. For FTP, this can also beenforced by using an URL that ends with ";type=A". This option causes datasent 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 andthis option is usually pointless, unless you use it to override a previouslyset option that sets a different authentication method (such as --ntlm,--digest and --negotiate).

If this option is used several times, the following occurrences make nodifference.

--ciphers <list of ciphers>
(SSL) Specifies which ciphers to use in the connection. The list of ciphersmust 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 libcurlsupports, and return the uncompressed document. If this option is used andthe server sends an unsupported encoding, Curl will report an error.

If this option is used several times, each occurrence will toggle it on/off.

--connect-timeout <seconds>
Maximum time in seconds that you allow the connection to the server to take.This only limits the connection phase, once curl has connected this option isof 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 completedoperation. Curl writes all cookies previously read from a specified file aswell as all cookies received from remote server(s). If no cookies are known,no file will be written. The file will be written using the Netscape cookiefile format. If you set the file name to a single dash, "-", the cookies willbe written to stdout.

NOTEIf the cookie jar can't be created or written to, the whole curl operationwon't fail or even report an error clearly. Using -v will get a warningdisplayed, but that is the only visible feedback you get about this possiblylethal situation.

If this option is used several times, the last specified file name will beused.

-C/--continue-at <offset>
Continue/Resume a previous file transfer at the given offset. The given offsetis the exact number of bytes that will be skipped counted from the beginningof the source file before it is transferred to the destination. If used withuploads, the ftp server command SIZE will not be used by curl.

Use "-C -" to tell curl to automatically find out where/how to resume thetransfer. 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 necessarylocal directory hierarchy as needed. This option creates the dirs mentionedwith the -o option, nothing else. If the -o file name uses no dir or if thedirs 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 nodifference.

-d/--data <data>
(HTTP) Sends the specified data in a POST request to the HTTP server, in a waythat can emulate as if a user has filled in a HTML form and pressed the submitbutton. Note that the data is sent exactly as specified with no extraprocessing (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 thecontent-type application/x-www-form-urlencoded. Compare to -F/--form. Ifthis option is used more than once on the same command line, the data piecesspecified will be merged together with a separating &-letter. Thus, using '-dname=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 toread the data from, or - if you want curl to read the data from stdin. Thecontents of the file must already be url-encoded. Multiple files can also bespecified. Posting data from a file named 'foobar' would thus be done with--data @foobar".

To post data purely binary, you should instead use the --data-binaryoption.

-d/--data is the same as --data-ascii.

If this option is used several times, the ones following the first willappend 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 willappend 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 keptas-is. If you want to post a binary file without the strip-newlines feature ofthe --data-ascii option, this is for you.

If this option is used several times, the ones following the first willappend data.

--digest
(HTTP) Enables HTTP Digest authentication. This is a authentication thatprevents the password from being sent over the wire in clear text. Use this incombination with the normal -u/--user option to set user name andpassword. See also --ntlm, --negotiate and --anyauth forrelated options.

If this option is used several times, the following occurrences make nodifference.

--disable-eprt
(FTP) Tell curl to disable the use of the EPRT and LPRT commands when doingactive FTP transfers. Curl will normally always first attempt to use EPRT,then LPRT before using PORT, but with this option, it will use PORT rightaway. EPRT and LPRT are extensions to the original FTP protocol, may not workon all servers but enable more functionality in a better way than thetraditional PORT command.

If this option is used several times, each occurrence will toggle this on/off.

--disable-epsv
(FTP) Tell curl to disable the use of the EPSV command when doing passive FTPtransfers. Curl will normally always first attempt to use EPSV before PASV,but with this option, it will not try using EPSV.

If this option is used several times, each occurrence will toggle this on/off.

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

This option is handy to use when you want to store the headers that a HTTPsite sends to you. Cookies from the headers could then be read in a secondcurl invoke by using the -b/--cookie option! The -c/--cookie-jaroption 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 alsobe set with the -H/--header flag of course. When used with-L/--location you can append ";auto" to the --referer URL to make curlautomatically set the previous URL when it follows a Location: header. The";auto" string can be used alone, even if you don't set an initial --referer.

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

--engine <name>
Select the OpenSSL crypto engine to use for cipheroperations. Use --engine list to print a list of build-time supportedengines. Note that not all (or none) of the engines may be available atrun-time.
--environment
(RISC OS ONLY) Sets a range of environment variables, using the names the -woption supports, to easier allow extraction of useful information after havingrun curl.

If this option is used several times, each occurrence will toggle this on/off.

--egd-file <file>
(HTTPS) Specify the path name to the Entropy Gathering Daemon socket. Thesocket 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 filewith HTTPS. The certificate must be in PEM format.If the optional password isn't specified, it will be queried for onthe terminal. Note that this certificate is the private key and the privatecertificate concatenated!

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

--cert-type <type>
(SSL) Tells curl what certificate type the provided certificate is in. PEM,DER and ENG are recognized types.

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

--cacert <CA certificate>
(HTTPS) Tells curl to use the specified certificate file to verify thepeer. The file may contain multiple CA certificates. The certificate(s) mustbe in PEM format.

curl recognizes the environment variable named 'CURL_CA_BUNDLE' if that isset, and uses the given path as a path to a CA cert bundle. This optionoverrides that variable.

The windows version of curl will automatically look for a CA certs file named'curl-ca-bundle.crt', either in the same directory as curl.exe, or in theCurrent 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 thepeer. The certificates must be in PEM format, and the directory must have beenprocessed using the c_rehash utility supplied with openssl. Using--capath can allow curl to make https connections much more efficientlythan using --cacert if the --cacert file contains many CAcertificates.

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 donelike this to better enable scripts etc to better deal with failed attempts. Innormal cases when a HTTP server fails to deliver a document, it returns anHTML document stating so (which often also describes why and more). This flagwill 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 passwordhas been provided, this data is sent off using the ACCT command. (Added in7.13.0)

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

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

If this option is used twice, the second will again disable directory creation.

--ftp-method [method]
(FTP) Control what method curl should use to reach a file on a FTP(S)server. The method argument should be one of the following alternatives:
multicwd
curl does a single CWD operation for each path part in the given URL. For deephierarchies this means very many commands. This is how RFC1738 says it shouldbe 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 fullpath to the server for all these commands. This is the fastest behavior.
singlecwd
curl does one CWD with the full target directory and then operates on the file"normally" (like in the multicwd case). This is somewhat more standardscompliant than 'nocwd' but without the full penalty of 'multicwd'.
--ftp-pasv
(FTP) Use PASV when transferring. PASV is the internal default behavior, butusing this option can be used to override a previous --ftp-port option. (Addedin 7.11.0)

If this option is used several times, the following occurrences make nodifference.

--ftp-alternative-to-user <command>
(FTP) If authenticating with the USER and PASS commands fails, send thiscommand. When connecting to Tumbleweed's Secure Transport server over FTPSusing a client certificate, using "SITE AUTH" will tell the server to retrievethe 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 responseto curl's PASV command when curl connects the data connection. Instead curlwill re-use the same IP address it already uses for the controlconnection. (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 suggestedaddress.

--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 thesubmit button. This causes curl to POST data using the Content-Typemultipart/form-data according to RFC1867. This enables uploading of binaryfiles etc. To force the 'content' part to be a file, prefix the file namewith an @ sign. To just get the content part from a file, prefix the file namewith the letter <. The difference between @ and < is then that @ makes a fileget attached in the post as a file upload, while the < makes a text field andjust get the contents for that text field from a file.

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

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

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

You can also tell curl what Content-Type to use by using 'type=', in a mannersimilar 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 bysetting 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 namedparameter is used literally. Leading '@' and '<' characters, and the';type=' string in the value have no special meaning. Use this in preferenceto --form if there's any possibility that the string value mayaccidentally 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 beinginterpreted by curl itself. Note that these letters are not normal legal URLcontents 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 POSTrequest that otherwise would be used. The data will be appended to the URLwith a '?' separator.

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

If this option is used several times, the following occurrences make nodifference.

-h/--help
Usage help.
-H/--header <header>
(HTTP) Extra header to use when getting a web page. You may specify any numberof extra headers. Note that if you should add a custom header that has thesame name as one of the internal ones curl would use, your externally setheader will be used instead of the internal one. This allows you to make eventrickier stuff than curl would normally do. You should not replace internallyset headers without knowing perfectly well what you're doing. Replacing aninternal header with one without content on the right side of the colon willprevent that header from appearing.

curl will make sure that each header you add/replace get sent with the properend of line marker, you should thus not add that as a part of the headercontent: do not add newlines or carriage returns they will only mess things upfor 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 serversrunning Apache 1.x, which will report incorrect Content-Length for fileslarger than 2 gigabytes.
-i/--include
(HTTP)Include the HTTP-header in the output. The HTTP-header includes thingslike 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 interfacename, 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 HEADwhich this uses to get nothing but the header of a document. When usedon a FTP or FILE file, curl displays the file size and last modificationtime 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 willmake it discard all "session cookies". This will basically have the same effectas if a new session is started. Typical browsers always discard sessioncookies when they're closed down.

If this option is used several times, each occurrence will toggle this on/off.

-k/--insecure
(SSL) This option explicitly allows curl to perform "insecure" SSL connectionsand transfers. All SSL connections are attempted to be made secure by usingthe CA certificate bundle installed by default. This makes all connectionsconsidered "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 thisseparate 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 providedprivate 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 andshould be one of 'clear', 'safe', 'confidential' or 'private'. Should you usea level that is not one of these, 'private' will instead be used.

This option requires that the library was built with kerberos4 support. Thisis not very common. Use -V/--version to see if your curl supports it.

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

-K/--config <config file>
Specify which config file to read curl arguments from. The config file is atext file in which command line arguments can be written which then will beused as if they were written on the actual command line. Options and theirparameters must be specified on the same config file line. If the parameter isto contain white spaces, the parameter must be enclosed within quotes. If thefirst column of a config line is a '#' character, the rest of the line will betreated 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 specifyit using the --url option, and not by simply writing the URL on its ownline. 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 defaultconfig file and uses it if found. The default config file is checked for inthe following places in this order:

1) curl tries to find the "home dir": It first checks for the CURL_HOME andthen the HOME environment variables. Failing that, it uses getpwuid() onunix-like systems (which returns the home dir given the current user in yoursystem). On Windows, it then checks for the APPDATA variable, or as a lastresort the '%USERPROFILE%Application Data'.

2) On windows, if there is no _curlrc file in the home dir, it checks for onein the same dir the executable curl is placed. On unix-like systems, it willsimply 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 usefulif you have a limited pipe and you'd like your transfer not use your entirebandwidth.

The given speed is measured in bytes/second, unless a suffix is appended.Appending 'k' or 'K' will count the number as kilobytes, 'm' or M' makes itmegabytes 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 takeprecedence and might cripple the rate-limiting slightly, to help keeping thespeed-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 FTPdirectory since the normal directory view doesn't use a standard lookor format.

This option causes an FTP NLST command to be sent. Some FTP serverslist only files in their response to NLST; they do not includesubdirectories 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 theconnection(s). Note that port numbers by nature is a scarce resource thatwill be busy at times so setting this range to something too narrow mightcause unnecessary connection setup failures. (Added in 7.15.2)
-L/--location
(HTTP/HTTPS) If the server reports that the requested page has moved to adifferent 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 togetherwith -i/--include or -I/--head, headers from all requested pageswill be shown. When authentication is used, curl only sends its credentials tothe initial host. If a redirect takes curl to a different host, it won't beable to intercept the user+password. See also --location-trusted on howto 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 notintroduce a security breach if the site redirects you do a site to whichyou'll send your authentication info (which is plaintext in the case of HTTPBasic 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 filerequested is larger than this value, the transfer will not start and curl willreturn with exit code 63.

NOTE: The file size is not always known prior to download, and for such filesthis option has no effect even if the file transfer ends up being larger thanthis 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 isuseful for preventing your batch jobs from hanging for hours due to slownetworks 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 loginname and password. This is typically used for ftp on unix. If used with http,curl will enable user authentication. Seenetrc(4)orftp(1)for details on the file format. Curl will not complain if that filehasn't the right permissions (it should not be world nor groupreadable). The environment variable "HOME" is used to find the homedirectory.

A quick and very simple example of how to setup a .netrc to allow curlto 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 usageoptional and not mandatory as the --netrc does.
--negotiate
(HTTP) Enables GSS-Negotiate authentication. The GSS-Negotiate method wasdesigned by Microsoft and is used in their web applications. It is primarilymeant as a support for Kerberos5 authentication but may be also used alongwith another authentication methods. For more information see IETF draftdraft-brezak-spnego-http-04.txt.

This option requires that the library was built with GSSAPI support. This isnot very common. Use -V/--version to see if your version supportsGSS-Negotiate.

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

If this option is used several times, the following occurrences make nodifference.

-N/--no-buffer
Disables the buffering of the output stream. In normal work situations, curlwill use a standard buffered output stream that will have the effect that itwill 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 wasdesigned by Microsoft and is used by IIS web servers. It is a proprietaryprotocol, reversed engineered by clever people and implemented in curl basedon their efforts. This kind of behavior should not be endorsed, you shouldencourage everyone who uses NTLM to switch to a public and documentedauthentication method instead. Such as Digest.

If you want to enable NTLM for your proxy authentication, then use--proxy-ntlm.

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

If this option is used several times, the following occurrences make nodifference.

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

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

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

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

--pass <phrase>
(SSL) Pass phrase for the private key

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

--proxy-anyauth
Tells curl to pick a suitable authentication method when communicating withthe given proxy. This will cause an extra request/response round-trip. (Addedin 7.13.2)

If this option is used twice, the second will again disable the proxy use-anyauthentication.

--proxy-basic
Tells curl to use HTTP Basic authentication when communicating with the givenproxy. Use --basic for enabling HTTP Basic with a remote host. Basic isthe default authentication method curl uses with proxies.

If this option is used twice, the second will again disable proxy HTTP Basicauthentication.

--proxy-digest
Tells curl to use HTTP Digest authentication when communicating with the givenproxy. 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 givenproxy. 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-HTTPprotocols to attempt to tunnel through the proxy instead of merely using it todo HTTP-like operations. The tunnel approach is made with the HTTP proxyCONNECT request and requires that the proxy allows direct connect to theremote 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. Thisswitch makes Curl use the PORT command instead of PASV. In practice, PORTtells the server to connect to the client's specified address and port, whilePASV 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 controlconnection

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

-q
If used as the first parameter on the command line, the curlrc configfile will not be read and used. See the -K/--config for details on thedefault config file search path.
-Q/--quote <command>
(FTP) Send an arbitrary command to the remote FTP server. Quote commands aresent BEFORE the transfer is taking place (just after the initial PWD commandto be exact). To make commands take place after a successful transfer, prefixthem with a dash '-'. To make commands get sent after libcurl has changedworking directory, just before the transfer command(s), prefix the commandwith '+'. You may specify any amount of commands. If the server returnsfailure for one of the commands, the entire operation will be aborted. Youmust 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 asrandom 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 FTPserver. 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 multipartresponse!

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

FTP range downloads only support the simple syntax 'start-stop' (optionallywith 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 theremote file, and if that is available make the local file get that sametimestamp.

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, itwill retry this number of times before giving up. Setting the number to 0makes 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 thenfor all forthcoming retries it will double the waiting time until it reaches10 minutes which then will be the delay between the rest of the retries. Byusing --retry-delay you disable this exponential backoff algorithm. Seealso --retry-max-time to limit the total time allowed forretries. (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 hasfailed with a transient error (it changes the default backoff time algorithmbetween retries). This option is only interesting if --retry is alsoused. 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 bedone as usual (see --retry) as long as the timer hasn't reached thisgiven limit. Notice that if the timer hasn't reached the limit, the requestwill be made and while performing, it may take longer than this given timeperiod. 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. MakesCurl mute.

If this option is used twice, the second will again disable silent mode.

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

If this option is used twice, the second will again disable show error.

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

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

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

--socks5 <host[:port]>
Use the specified SOCKS5 proxy. If the port number is not specified, it isassumed at port 1080. (Added in 7.11.1)

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

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

--stderr <file>
Redirect all writes to stderr to the specified file instead. If the file nameis a plain '-', it is instead written to stdout. This option has no point whenyou'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 fordetails 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 filepart in the specified URL, Curl will append the local file name. NOTE that youmust use a trailing / on the last directory to really prove to Curl that thereis no file name or curl will think that your last directory name is the remotefile name to use. That will most likely cause the upload operation to fail. Ifthis 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 pairspecifies what to upload and to where. curl also supports "globbing" of the -Targument, meaning that you can upload multiple files to a single URL by usingthe 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, includingdescriptive information, to the given output file. Use "-" as filename to havethe 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, includingdescriptive information, to the given output file. Use "-" as filename to havethe output sent to stdout.

This is very similar to --trace, but leaves out the hex part and onlyshows the ASCII part of the dump. It makes smaller output that might be easierto read for untrained humans.

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

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

If this option is used several times, each occurrence will toggle it on/off.

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

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

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

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

If you use an SSPI-enabled curl binary and do NTLM autentication, you canforce curl to pick up the user name and password from your environment bysimply 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 specifyURL(s) in a config file.

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

-v/--verbose
Makes the fetching more verbose/talkative. Mostly usable for debugging. Linesstarting 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/--includemight be option you're looking for.

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

If this option is used twice, the second will again disable verbose.

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

The first line includes the full version of curl, libcurl and other 3rd partylibraries linked with the executable.

The second line (starts with "Protocols:") shows all protocols that libcurlreports to support.

The third line (starts with "Features:") shows specific features libcurlreports 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-trackingand 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 willauthenticate with your current user and password.
-w/--write-out <format>
Defines what to display on stdout after a completed and successfuloperation. The format is a string that may contain plain text mixed with anynumber of variables. The string can be specified as "string", to get read froma particular file you specify it "@filename" and to tell curl to read theformat from stdin you write "@-".

The variables present in the output format will be substituted by the value ortext that curl thinks fit, as described below. All variables are specifiedlike %{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 tabspace with \t.

NOTE:The %-letter is a special letter in the win32-environment, where alloccurrences 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 curlto follow location: headers.
http_code
The numerical code that was found in the last retrieved HTTP(S) page.
http_connect
The numerical code that was found in the last response (from a proxy) to acurl CONNECT request. (Added in 7.12.4)
time_total
The total time, in seconds, that the full operation lasted. The time will bedisplayed with millisecond resolution.
time_namelookup
The time, in seconds, it took from the start until the name resolving wascompleted.
time_connect
The time, in seconds, it took from the start until the connect to the remotehost (or proxy) was completed.
time_pretransfer
The time, in seconds, it took from the start until the file transfer is justabout to begin. This includes all pre-transfer commands and negotiations thatare specific to the particular protocol(s) involved.
time_redirect
The time, in seconds, it took for all redirection steps include name lookup,connect, pretransfer and transfer before final transaction wasstarted. time_redirect shows the complete execution time for multipleredirections. (Added in 7.12.3)
time_starttransfer
The time, in seconds, it took from the start until the first byte is just aboutto be transferred. This includes time_pretransfer and also the time theserver needs to calculate the result.
size_download
The total amount of bytes that were downloaded.
size_upload
The total amount of bytes that were uploaded.
size_header
The total amount of bytes of the downloaded headers.
size_request
The total amount of bytes that were sent in the HTTP request.
speed_download
The average download speed that curl measured for the complete download.
speed_upload
The average upload speed that curl measured for the complete upload.
content_type
The Content-Type of the requested document, if there was any.
num_connects
Number of new connects made in the recent transfer. (Added in 7.12.3)
num_redirects
Number of redirects that were followed in the request. (Added in 7.12.3)
ftp_entry_path
The initial path libcurl ended up in when logging on to the remote FTPserver. (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 assumedat port 1080.

This option overrides existing environment variables that sets proxy touse. 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 willtransparently be converted to HTTP. It means that certain protocol specificoperations might not be available. This is not the case if you can tunnelthrough the proxy, as done with the -p/--proxytunnel option.

Starting with 7.14.1, the proxy host can be specified the exact same way asthe proxy environment variables, include protocol prefix (http://) andembedded user + password.

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

-X/--request <command>
(HTTP) Specifies a custom request method to use when communicating with theHTTP server. The specified request will be used instead of the methodotherwise used (which defaults to GET). Read the HTTP 1.1 specification fordetails and explanations.

(FTP)Specifies a custom FTP command to use instead of LIST when doing file listswith 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-timeperiod, the download gets aborted. If speed-time is used, the defaultspeed-limit will be 1 unless set with -y.

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

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

-Y/--speed-limit <speed>
If a download is slower than this given speed, in bytes per second, forspeed-time seconds it gets aborted. speed-time is set with -Y and is 30 ifnot 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 anddate, or one that has been modified before that time. The date expression canbe all sorts of date strings or if it doesn't match any internal ones, ittries to get the time from a given file name instead! See thecurl_getdate(3) man pages for date expression details.

Start the date expression with a dash (-) to make it request for a documentthat is older than the given date/time, default is a document that is newerthan 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/--locationis used, this option can be used to prevent curl from following redirections"in absurdum". By default, the limit is set to 50 redirections. Set thisoption to -1 to make it limitless.

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

-0/--http1.0
(HTTP) Forces curl to issue its requests using HTTP 1.0 instead of using itsinternally 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 afile from, while the "normal" URL will be used as target URL, the file thatwill 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 (whichit is if it is ipv6-capable), this option tells libcurl to resolve names toIPv4 addresses only.
-6/--ipv6
If libcurl is capable of resolving an address to multiple IP versions (whichit is if it is ipv6-capable), this option tells libcurl to resolve names toIPv6 addresses only.
-#/--progress-bar
Make curl display progress information as a progress bar instead of thedefault 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 errormessages 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 particularresource or directory you wanted to reach. Most often you tried to change to adirectory that doesn't exist on the server.
10
FTP user/password incorrect. Either one or both were not accepted by theserver.
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 similar) commandfailed.
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 anothererror with the HTTP error code being 400 or above. This return code onlyappears 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 FTPuploading.
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 theconditions.
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 PORTcommand, try doing a transfer using PASV instead!
31
FTP couldn't use REST. The REST command failed. This command is used forresumed FTP transfers.
32
FTP couldn't use SIZE. The SIZE command failed. The command is an extensionto 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 operation.
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 maximum 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 onesare meant to never change.
 

AUTHORS / CONTRIBUTORS

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

WWW

http://curl.haxx.se 

FTP

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

SEE ALSO

ftp(1),wget(1)


 

Index

NAME
SYNOPSIS
DESCRIPTION
URL
PROGRESS METER
OPTI