curl(1) Curl Manual curl(1) NAME curl - transfer a URL SYNOPSIS curl [options] [URL...] DESCRIPTION curl is a tool to transfer data from or to a server, using one of the supported protocols (HTTP, HTTPS, FTP, FTPS, GOPHER, DICT, TELNET, LDAP or FILE). The command is designed to work without user interaction. curl offers a busload of useful tricks like proxy support, user authen- tication, ftp upload, HTTP post, SSL (https:) connections, cookies, file transfer resume and more. As you will see below, the amount of features will make your head spin! curl is powered by libcurl for all transfer-related features. See libcurl(3) for details. URL The URL syntax is protocol dependent. You'll find a detailed descrip- tion in RFC 2396. You can specify multiple URLs or parts of URLs by writing part sets within braces as in: http://site.{one,two,three}.com or you can get sequences of alphanumeric series by using [] as in: ftp://ftp.numericals.com/file[1-100].txt ftp://ftp.numericals.com/file[001-100].txt (with leading zeros) ftp://ftp.letters.com/file[a-z].txt No nesting of the sequences is supported at the moment, but you can use several ones next to each other: http://any.org/archive[1996-1999]/vol[1-4]/part{a,b,c}.html You can specify any amount of URLs on the command line. They will be fetched in a sequential manner in the specified order. 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. OPTIONS -a/--append (FTP) When used in an FTP upload, this will tell curl to append to the target file instead of overwriting it. If the file doesn't exist, it will be created. If this option is used twice, the second one will disable append mode again. -A/--user-agent (HTTP) Specify the User-Agent string to send to the HTTP server. Some badly done CGIs fail if its not set to "Mozilla/4.0". To encode blanks in the string, surround the string with single quote marks. This can also be set with the -H/--header option of course. If this option is set more than once, the last one will be the one that's used. --anyauth (HTTP) Tells curl to figure out authentication method by itself, and use the most secure one the remote site claims it supports. This is done by first doing a request and checking the response- headers, thus inducing an extra network round-trip. This is used instead of setting a specific authentication method, which you can do with --basic, --digest, --ntlm, and --negotiate. (Added in 7.10.6) Note that using --anyauth is not recommended if you do uploads from stdin, since it may require data to be sent twice and then the client must be able to rewind. If the need should arise when uploading from stdin, the upload operation will fail. If this option is used several times, the following occurrences make no difference. -b/--cookie (HTTP) Pass the data to the HTTP server as a cookie. It is sup- posedly the data previously received from the server in a "Set- Cookie:" line. The data should be in the format "NAME1=VALUE1; NAME2=VALUE2". If no '=' letter is used in the line, it is treated as a file- name to use to read previously stored cookie lines from, which should be used in this session if they match. Using this method also activates the "cookie parser" which will make curl record incoming cookies too, which may be handy if you're using this in combination with the -L/--location option. The file format of the file to read cookies from should be plain HTTP headers or the Netscape/Mozilla cookie file format. NOTE that the file specified with -b/--cookie is only used as input. No cookies will be stored in the file. To store cookies, use the -c/--cookie-jar option or you could even save the HTTP headers to a file using -D/--dump-header! If this option is set more than once, the last one will be the one that's used. -B/--use-ascii Enable ASCII transfer when using FTP or LDAP. For FTP, this can also be enforced by using an URL that ends with ";type=A". This option causes data sent to stdout to be in text mode for win32 systems. If this option is used twice, the second one will disable ASCII usage. --basic (HTTP) Tells curl to use HTTP Basic authentication. This is the default and this option is usually pointless, unless you use it to override a previously set option that sets a different authentication method (such as --ntlm, --digest and --negoti- ate). (Added in 7.10.6) If this option is used several times, the following occurrences make no difference. --ciphers (SSL) Specifies which ciphers to use in the connection. The list of ciphers must be using valid ciphers. Read up on SSL cipher list details on this URL: http://www.openssl.org/docs/apps/ciphers.html If this option is used several times, the last one will override the others. --compressed (HTTP) Request a compressed response using one of the algorithms libcurl supports, and return the uncompressed document. If this option is used and the server sends an unsupported encoding, Curl will report an error. If this option is used several times, each occurrence will tog- gle it on/off. --connect-timeout Maximum time in seconds that you allow the connection to the server to take. This only limits the connection phase, once curl has connected this option is of no more use. See also the -m/--max-time option. If this option is used several times, the last one will be used. -c/--cookie-jar Specify to which file you want curl to write all cookies after a completed operation. Curl writes all cookies previously read from a specified file as well as all cookies received from remote server(s). If no cookies are known, no file will be writ- ten. The file will be written using the Netscape cookie file format. If you set the file name to a single dash, "-", the cookies will be written to stdout. NOTE If the cookie jar can't be created or written to, the whole curl operation won't fail or even report an error clearly. Using -v will get a warning displayed, but that is the only visible feedback you get about this possibly lethal situation. If this option is used several times, the last specified file name will be used. -C/--continue-at Continue/Resume a previous file transfer at the given offset. The given offset is the exact number of bytes that will be skipped counted from the beginning of the source file before it is transferred to the destination. If used with uploads, the ftp server command SIZE will not be used by curl. Use "-C -" to tell curl to automatically find out where/how to resume the transfer. It then uses the given output/input files to figure that out. If this option is used several times, the last one will be used. --create-dirs When used in conjunction with the -o option, curl will create the necessary local directory hierarchy as needed. This option creates the dirs mentioned with the -o option, nothing else. If the -o file name uses no dir or if the dirs it mentions already exist, no dir will be created. To create remote directories when using FTP, try --ftp-create- dirs. --crlf (FTP) Convert LF to CRLF in upload. Useful for MVS (OS/390). If this option is used twice, the second will again disable crlf converting. -d/--data (HTTP) Sends the specified data in a POST request to the HTTP server, in a way that can emulate as if a user has filled in a HTML form and pressed the submit button. Note that the data is sent exactly as specified with no extra processing (with all newlines cut off). The data is expected to be "url-encoded". This will cause curl to pass the data to the server using the content-type application/x-www-form-urlencoded. Compare to -F/--form. If this option is used more than once on the same command line, the data pieces specified will be merged together with a separating &-letter. Thus, using '-d name=daniel -d skill=lousy' would generate a post chunk that looks like 'name=daniel&skill=lousy'. If you start the data with the letter @, the rest should be a file name to read the data from, or - if you want curl to read the data from stdin. The contents of the file must already be url-encoded. Multiple files can also be specified. Posting data from a file named 'foobar' would thus be done with --data @foo- bar". To post data purely binary, you should instead use the --data- binary option. -d/--data is the same as --data-ascii. If this option is used several times, the ones following the first will append data. --data-ascii (HTTP) This is an alias for the -d/--data option. If this option is used several times, the ones following the first will append data. --data-binary (HTTP) This posts data in a similar manner as --data-ascii does, although when using this option the entire context of the posted data is kept as-is. If you want to post a binary file without the strip-newlines feature of the --data-ascii option, this is for you. If this option is used several times, the ones following the first will append data. --digest (HTTP) Enables HTTP Digest authentication. This is a authentica- tion that prevents the password from being sent over the wire in clear text. Use this in combination with the normal -u/--user option to set user name and password. See also --ntlm, --negoti- ate and --anyauth for related options. (Added in curl 7.10.6) If this option is used several times, the following occurrences make no difference. --disable-eprt (FTP) Tell curl to disable the use of the EPRT and LPRT commands when doing active FTP transfers. Curl will normally always first attempt to use EPRT, then LPRT before using PORT, but with this option, it will use PORT right away. EPRT and LPRT are exten- sions to the original FTP protocol, may not work on all servers but enable more functionality in a better way than the tradi- tional PORT command. (Added in 7.10.5) If this option is used several times, each occurrence will tog- gle this on/off. --disable-epsv (FTP) Tell curl to disable the use of the EPSV command when doing passive FTP transfers. Curl will normally always first attempt to use EPSV before PASV, but with this option, it will not try using EPSV. If this option is used several times, each occurrence will tog- gle this on/off. -D/--dump-header Write the protocol headers to the specified file. This option is handy to use when you want to store the headers that a HTTP site sends to you. Cookies from the headers could then be read in a second curl invoke by using the -b/--cookie option! The -c/--cookie-jar option is however a better way to store cookies. When used on FTP, the ftp server response lines are considered being "headers" and thus are saved there. If this option is used several times, the last one will be used. -e/--referer (HTTP) Sends the "Referer Page" information to the HTTP server. This can also be set with the -H/--header flag of course. When used with -L/--location you can append ";auto" to the referer URL to make curl automatically set the previous URL when it fol- lows a Location: header. The ";auto" string can be used alone, even if you don't set an initial referer. If this option is used several times, the last one will be used. --engine Select the OpenSSL crypto engine to use for cipher operations. Use --engine list to print a list of build-time supported engines. Note that not all (or none) of the engines may be available at run-time. --environment (RISC OS ONLY) Sets a range of environment variables, using the names the -w option supports, to easier allow extraction of use- ful information after having run curl. If this option is used several times, each occurrence will tog- gle this on/off. --egd-file (HTTPS) Specify the path name to the Entropy Gathering Daemon socket. The socket is used to seed the random engine for SSL connections. See also the --random-file option. -E/--cert (HTTPS) Tells curl to use the specified certificate file when getting a file with HTTPS. The certificate must be in PEM for- mat. If the optional password isn't specified, it will be queried for on the terminal. Note that this certificate is the private key and the private certificate concatenated! If this option is used several times, the last one will be used. --cert-type (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 (HTTPS) Tells curl to use the specified certificate file to ver- ify the peer. The file may contain multiple CA certificates. The certificate(s) must be in PEM format. curl recognizes the environment variable named 'CURL_CA_BUNDLE' if that is set, and uses the given path as a path to a CA cert bundle. This option overrides that variable. The windows version of curl will automatically look for a CA certs file named 'curl-ca-bundle.crt', either in the same direc- tory as curl.exe, or in the Current Working Directory, or in any folder along your PATH. If this option is used several times, the last one will be used. --capath (HTTPS) Tells curl to use the specified certificate directory to verify the peer. The certificates must be in PEM format, and the directory must have been processed using the c_rehash utility supplied with openssl. Using --capath can allow curl to make https connections much more efficiently than using --cacert if the --cacert file contains many CA certificates. If this option is used several times, the last one will be used. -f/--fail (HTTP) Fail silently (no output at all) on server errors. This is mostly done like this to better enable scripts etc to better deal with failed attempts. In normal cases when a HTTP server fails to deliver a document, it returns a HTML document stating so (which often also describes why and more). This flag will prevent curl from outputting that and fail silently instead. If this option is used twice, the second will again disable silent failure. --ftp-account [data] (FTP) When an FTP server asks for "account data" after user name and password has been provided, this data is sent off using the ACCT command. (Added in 7.13.0) If this option is used twice, the second will override the pre- vious use. --ftp-create-dirs (FTP) When an FTP URL/operation uses a path that doesn't cur- rently exist on the server, the standard behavior of curl is to fail. Using this option, curl will instead attempt to create missing directories. (Added in 7.10.7) If this option is used twice, the second will again disable silent failure. --ftp-pasv (FTP) Use PASV when transfering. PASV is the internal default behavior, but using this option can be used to override a previ- ous --ftp-port option. (Added in 7.11.0) If this option is used twice, the second will again disable silent failure. --ftp-ssl (FTP) Make the FTP connection switch to use SSL/TLS. (Added in 7.11.0) If this option is used twice, the second will again disable this. -F/--form (HTTP) This lets curl emulate a filled in form in which a user has pressed the submit button. This causes curl to POST data using the Content-Type multipart/form-data according to RFC1867. This enables uploading of binary files etc. To force the 'con- tent' part to be a file, prefix the file name with an @ sign. To just get the content part from a file, prefix the file name with the letter <. The difference between @ and < is then that @ makes a file get attached in the post as a file upload, while the < makes a text field and just get the contents for that text field from a file. Example, to send your password file to the server, where 'pass- word' is the name of the form-field to which /etc/passwd will be the input: curl -F password=@/etc/passwd www.mypasswords.com To read the file's content from stdin instead of a file, use - where the file name should've been. This goes for both @ and < constructs. You can also tell curl what Content-Type to use by using 'type=', in a manner similar to: curl -F "web=@index.html;type=text/html" url.com or curl -F "name=daniel;type=text/foo" url.com You can also explicitly change the name field of an file upload part by setting filename=, like this: curl -F "file=@localfile;filename=nameinpost" url.com See further examples and details in the MANUAL. This option can be used multiple times. -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 used multiple times, nothing special happens. -h/--help Usage help. -H/--header
(HTTP) Extra header to use when getting a web page. You may specify any number of extra headers. Note that if you should add a custom header that has the same name as one of the internal ones curl would use, your externally set header will be used instead of the internal one. This allows you to make even trick- ier stuff than curl would normally do. You should not replace internally set headers without knowing perfectly well what you're doing. Replacing an internal header with one without con- tent on the right side of the colon will prevent that header from appearing. See also the -A/--user-agent and -e/--referer options. This option can be used multiple times to add/replace/remove multiple headers. -i/--include (HTTP) Include the HTTP-header in the output. The HTTP-header includes things like server-name, date of the document, HTTP- version and more... If this option is used twice, the second will again disable header include. --interface Perform an operation using a specified interface. You can enter interface name, IP address or host name. An example could look like: curl --interface eth0:1 http://www.netscape.com/ If this option is used several times, the last one will be used. -I/--head (HTTP/FTP/FILE) Fetch the HTTP-header only! HTTP-servers feature the command HEAD which this uses to get nothing but the header of a document. When used on a FTP or FILE file, curl displays the file size and last modification time only. If this option is used twice, the second will again disable header only. -j/--junk-session-cookies (HTTP) When curl is told to read cookies from a given file, this option will make it discard all "session cookies". This will basically have the same effect as if a new session is started. Typical browsers always discard session cookies when they're closed down. (Added in 7.9.7) If this option is used several times, each occurrence will tog- gle this on/off. -k/--insecure (SSL) This option explicitly allows curl to perform "insecure" SSL connections and transfers. Starting with curl 7.10, all SSL connections will be attempted to be made secure by using the CA certificate bundle installed by default. This makes all connec- tions considered "insecure" to fail unless -k/--insecure is used. If this option is used twice, the second time will again disable it. --key (SSL) Private key file name. Allows you to provide your private key in this separate file. If this option is used several times, the last one will be used. --key-type (SSL) Private key file type. Specify which type your --key pro- vided private key is. DER, PEM and ENG are supported. If this option is used several times, the last one will be used. --krb4 (FTP) Enable kerberos4 authentication and use. The level must be entered and should be one of 'clear', 'safe', 'confidential' or 'private'. Should you use a level that is not one of these, 'private' will instead be used. This option requires that the library was built with kerberos4 support. This is not very common. Use -V/--version to see if your curl supports it. If this option is used several times, the last one will be used. -K/--config Specify which config file to read curl arguments from. The con- fig file is a text file in which command line arguments can be written which then will be used as if they were written on the actual command line. Options and their parameters must be speci- fied on the same config file line. If the parameter is to con- tain white spaces, the parameter must be inclosed within quotes. If the first column of a config line is a '#' character, the rest of the line will be treated as a comment. Specify the filename as '-' to make curl read the file from stdin. Note that to be able to specify a URL in the config file, you need to specify it using the --url option, and not by simply writing the URL on its own line. So, it could look similar to this: url = "http://curl.haxx.se/docs/" This option can be used multiple times. --limit-rate Specify the maximum transfer rate you want curl to use. This feature is useful if you have a limited pipe and you'd like your transfer not use your entire bandwidth. The given speed is measured in bytes/second, unless a suffix is appended. Appending 'k' or 'K' will count the number as kilo- bytes, 'm' or M' makes it megabytes while 'g' or 'G' makes it gigabytes. Examples: 200K, 3m and 1G. If you are also using the -Y/--speed-limit option, that option will take precedence and might cripple the rate-limiting slightly, to help keeping the speed-limit logic working. This option was introduced in curl 7.10. If this option is used several times, the last one will be used. -l/--list-only (FTP) When listing an FTP directory, this switch forces a name- only view. Especially useful if you want to machine-parse the contents of an FTP directory since the normal directory view doesn't use a standard look or format. This option causes an FTP NLST command to be sent. Some FTP servers list only files in their response to NLST; they do not include subdirectories and symbolic links. If this option is used twice, the second will again disable list only. -L/--location (HTTP/HTTPS) If the server reports that the requested page has a different location (indicated with the header line Location:) this flag will let curl attempt to reattempt the get on the new place. If used together with -i/--include or -I/--head, headers from all requested pages will be shown. If authentication is used, curl will only send its credentials to the initial host, so if a redirect takes curl to a different host, it won't inter- cept the user+password. See also --location-trusted on how to change this. If this option is used twice, the second will again disable location following. --location-trusted (HTTP/HTTPS) Like -L/--location, but will allow sending the name + password to all hosts that the site may redirect to. This may or may not introduce a security breach if the site redirects you do a site to which you'll send your authentication info (which is plaintext in the case of HTTP Basic authentication). If this option is used twice, the second will again disable location following. --max-filesize Specify the maximum size (in bytes) of a file to download. If the file requested is larger than this value, the transfer will not start and curl will return with exit code 63. NOTE: The file size is not always known prior to download, and for such files this option has no effect even if the file trans- fer ends up being larger than this given limit. This concerns both FTP and HTTP transfers. -m/--max-time 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. This doesn't work fully in win32 systems. See also the --connect- timeout option. If this option is used several times, the last one will be used. -M/--manual Manual. Display the huge help text. -n/--netrc Makes curl scan the .netrc file in the user's home directory for login name and password. This is typically used for ftp on unix. If used with http, curl will enable user authentication. See netrc(4) or ftp(1) for details on the file format. Curl will not complain if that file hasn't the right permissions (it should not be world nor group readable). The environment variable "HOME" is used to find the home directory. A quick and very simple example of how to setup a .netrc to allow curl to ftp to the machine host.domain.com with user name 'myself' and password machine host.domain.com login myself password secret If this option is used twice, the second will again disable netrc usage. --netrc-optional Very similar to --netrc, but this option makes the .netrc usage optional and not mandatory as the --netrc does. --negotiate (HTTP) Enables GSS-Negotiate authentication. The GSS-Negotiate method was designed by Microsoft and is used in their web appli- cations. It is primarily meant as a support for Kerberos5 authentication but may be also used along with another authenti- cation methods. For more information see IETF draft draft- brezak-spnego-http-04.txt. (Added in 7.10.6) This option requires that the library was built with GSSAPI sup- port. This is not very common. Use -V/--version to see if your version supports GSS-Negotiate. If this option is used several times, the following occurrences make no difference. -N/--no-buffer Disables the buffering of the output stream. In normal work sit- uations, curl will use a standard buffered output stream that will have the effect that it will output the data in chunks, not necessarily exactly when the data arrives. Using this option will disable that buffering. If this option is used twice, the second will again switch on buffering. --ntlm (HTTP) Enables NTLM authentication. The NTLM authentication method was designed by Microsoft and is used by IIS web servers. It is a proprietary protocol, reversed engineered by clever peo- ple and implemented in curl based on their efforts. This kind of behavior should not be endorsed, you should encourage everyone who uses NTLM to switch to a public and documented authentica- tion method instead. Such as Digest. (Added in 7.10.6) If you want to enable NTLM for your proxy authentication, then use --proxy-ntlm. This option requires that the library was built with SSL sup- port. Use -V/--version to see if your curl supports NTLM. If this option is used several times, the following occurrences make no difference. -o/--output Write output to instead of stdout. If you are using {} or [] to fetch multiple documents, you can use '#' followed by a number in the specifier. That variable will be replaced with the current string for the URL being fetched. Like in: curl http://{one,two}.site.com -o "file_#1.txt" or use several variables like: curl http://{site,host}.host[1-5].com -o "#1_#2" You may use this option as many times as you have number of URLs. See also the --create-dirs option to create the local directo- ries dynamically. -O/--remote-name Write output to a local file named like the remote file we get. (Only the file part of the remote file is used, the path is cut off.) The remote file name to use for saving is extracted from the given URL. Nothing else You may use this option as many times as you have number of URLs. --pass (SSL) Pass phrase for the private key If this option is used several times, the last one will be used. --proxy-basic Tells curl to use HTTP Basic authentication when communicating with the given proxy. Use --basic for enabling HTTP Basic with a remote host. Basic is the default authentication method curl uses with proxies. If this option is used twice, the second will again disable proxy HTTP Basic authentication. --proxy-digest Tells curl to use HTTP Digest authentication when communicating with the given proxy. Use --digest for enabling HTTP Digest with a remote host. If this option is used twice, the second will again disable proxy HTTP Digest. --proxy-ntlm Tells curl to use HTTP NTLM authentication when communicating with the given proxy. Use --ntlm for enabling NTLM with a remote host. If this option is used twice, the second will again disable proxy HTTP NTLM. -p/--proxytunnel When an HTTP proxy is used (-x/--proxy), this option will cause non-HTTP protocols to attempt to tunnel through the proxy instead of merely using it to do HTTP-like operations. The tun- nel approach is made with the HTTP proxy CONNECT request and requires that the proxy allows direct connect to the remote port number curl wants to tunnel through to. If this option is used twice, the second will again disable proxy tunnel. -P/--ftp-port
(FTP) Reverses the initiator/listener roles when connecting with ftp. This switch makes Curl use the PORT command instead of PASV. In practice, PORT tells the server to connect to the client's specified address and port, while PASV asks the server for an ip address and port to connect to.
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 - (any single-letter string) to make it pick the machine's default If this option is used several times, the last one will be used. Dis- able the use of PORT with --ftp-pasv. Disable the attempt to use the EPRT command instead of PORT by using --disable-eprt. EPRT is really PORT++. -q If used as the first parameter on the command line, the $HOME/.curlrc file will not be read and used as a config file. -Q/--quote (FTP) Send an arbitrary command to the remote FTP server. Quote commands are sent BEFORE the transfer is taking place (just after the initial PWD command to be exact). To make commands take place after a successful transfer, prefix them with a dash '-'. To make commands get sent after libcurl has changed working directory, just before the transfer command(s), prefix the com- mand with '+'. You may specify any amount of commands. If the server returns failure for one of the commands, the entire oper- ation will be aborted. You must send syntactically correct FTP commands as RFC959 defines. This option can be used multiple times. --random-file (HTTPS) Specify the path name to file containing what will be considered as random data. The data is used to seed the random engine for SSL connections. See also the --egd-file option. -r/--range (HTTP/FTP) Retrieve a byte range (i.e a partial document) from a HTTP/1.1 or FTP server. Ranges can be specified in a number of ways. 0-499 specifies the first 500 bytes 500-999 specifies the second 500 bytes -500 specifies the last 500 bytes 9500 specifies the bytes from offset 9500 and forward 0-0,-1 specifies the first and last byte only(*)(H) 500-700,600-799 specifies 300 bytes from offset 500(H) 100-199,500-599 specifies two separate 100 bytes ranges(*)(H) (*) = NOTE that this will cause the server to reply with a multipart response! You should also be aware that many HTTP/1.1 servers do not have this feature enabled, so that when you attempt to get a range, you'll instead get the whole document. FTP range downloads only support the simple syntax 'start-stop' (optionally with one of the numbers omitted). It depends on the non-RFC command SIZE. If this option is used several times, the last one will be used. -R/--remote-time When used, this will make libcurl attempt to figure out the timestamp of the remote file, and if that is available make the local file get that same timestamp. If this option is used twice, the second time disables this again. --retry If a transient error is returned when curl tries to perform a transfer, it will retry this number of times before giving up. Setting the number to 0 makes curl do no retries (which is the default). Transient error means either: a timeout, an FTP 5xx response code or an HTTP 5xx response code. When curl is about to retry a transfer, it will first wait one second and then for all forthcoming retries it will double the waiting time until it reaches 10 minutes which then will be the delay between the rest of the retries. By using --retry-delay you disable this exponential backoff algorithm. See also --retry-max-time to limit the total time allowed for retries. (Option added in 7.12.3) If this option is used multiple times, the last occurrence decide the amount. --retry-delay Make curl sleep this amount of time between each retry when a transfer has failed with a transient error (it changes the default backoff time algorithm between retries). This option is only interesting if --retry is also used. Setting this delay to zero will make curl use the default backoff time. (Option added in 7.12.3) If this option is used multiple times, the last occurrence decide the amount. --retry-max-time 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. (Option added in 7.12.3) If this option is used multiple times, the last occurrence decide the amount. -s/--silent Silent mode. Don't show progress meter or error messages. Makes Curl mute. If this option is used twice, the second will again disable mute. -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. --socks Use the specified SOCKS5 proxy. If the port number is not speci- fied, it is assumed at port 1080. (Option added in 7.11.1) This option overrides any previous use of -x/--proxy, as they are mutually exclusive. If this option is used several times, the last one will be used. --stderr Redirect all writes to stderr to the specified file instead. If the file name is a plain '-', it is instead written to stdout. This option has no point when you're using a shell with decent redirecting capabilities. If this option is used several times, the last one will be used. --tcp-nodelay Turn on the TCP_NODELAY option. See the curl_easy_setopt(3) man page for details about this option. (Added in 7.11.2) If this option is used several times, each occurrence toggles this on/off. -t/--telnet-option Pass options to the telnet protocol. Supported options are: TTYPE= Sets the terminal type. XDISPLOC= Sets the X display location. NEW_ENV= Sets an environment variable. -T/--upload-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. Before 7.10.8, when this option was used several times, the last one was used. In curl 7.10.8 and later, you can specify one -T for each URL on the command line. Each -T + URL pair specifies what to upload and to where. curl also supports "globbing" of the -T argument, meaning that you can upload multiple files to a single URL by using the same URL globbing style supported in the URL, like this: curl -T "{file1,file2}" http://www.uploadtothissite.com or even curl -T "img[1-1000].png" ftp://ftp.picturemania.com/upload/ --trace Enables a full trace dump of all incoming and outgoing data, including descriptive information, to the given output file. Use "-" as filename to have the output sent to stdout. If this option is used several times, the last one will be used. (Added in 7.9.7) --trace-ascii Enables a full trace dump of all incoming and outgoing data, including descriptive information, to the given output file. Use "-" as filename to have the output sent to stdout. This is very similar to --trace, but leaves out the hex part and only shows the ASCII part of the dump. It makes smaller output that might be easier to read for untrained humans. If this option is used several times, the last one will be used. (Added in 7.9.7) -u/--user Specify user and password to use for server authentication. Overrides -n/--netrc and --netrc-optional. If this option is used several times, the last one will be used. -U/--proxy-user Specify user and password to use for proxy authentication. If this option is used several times, the last one will be used. --url Specify a URL to fetch. This option is mostly handy when you want to specify URL(s) in a config file. This option may be used any number of times. To control where this URL is written, use the -o/--output or the -O/--remote-name options. -v/--verbose Makes the fetching more verbose/talkative. Mostly usable for debugging. Lines starting with '>' means data sent by curl, '<' means data received by curl that is hidden in normal cases and lines starting with '*' means additional info provided by curl. Note that if you only want HTTP headers in the output, -i/--include might be option you're looking for. If you think this option still doesn't give you enough details, consider using --trace or --trace-ascii instead. If this option is used twice, the second will again disable ver- bose. -V/--version Displays information about curl and the libcurl version it uses. The first line includes the full version of curl, libcurl and other 3rd party libraries linked with the executable. The second line (starts with "Protocols:") shows all protocols that libcurl reports to support. The third line (starts with "Features:") shows specific features libcurl reports to offer. Available features include: IPv6 You can use IPv6 with this. krb4 Krb4 for ftp is supported. SSL HTTPS and FTPS are supported. libz Automatic decompression of compressed files over HTTP is supported. NTLM NTLM authentication is supported. GSS-Negotiate Negotiate authentication is supported. Debug This curl uses a libcurl built with Debug. This enables more error-tracking and memory debugging etc. For curl- developers only! AsynchDNS This curl uses asynchronous name resolves. SPNEGO SPNEGO Negotiate authentication is supported. Largefile This curl supports transfers of large files, files larger than 2GB. IDN This curl supports IDN - international domain names. -w/--write-out Defines what to display after a completed and successful opera- tion. The format is a string that may contain plain text mixed with any number of variables. The string can be specified as "string", to get read from a particular file you specify it "@filename" and to tell curl to read the format from stdin you write "@-". The variables present in the output format will be substituted by the value or text that curl thinks fit, as described below. All variables are specified like %{variable_name} and to output a normal % you just write them like %%. You can output a newline by using \n, a carriage return with \r and a tab space with \t. NOTE: The %-letter is a special letter in the win32-environment, where all occurrences of % must be doubled when using this option. Available variables are at this point: url_effective The URL that was fetched last. This is mostly meaningful if you've told curl to follow loca- tion: headers. http_code The numerical code that was found in the last retrieved HTTP(S) page. http_connect The numerical code that was found in the last response (from a proxy) to a curl CONNECT request. (Added in 7.12.4) time_total The total time, in seconds, that the full opera- tion lasted. The time will be displayed with mil- lisecond resolution. time_namelookup The time, in seconds, it took from the start until the name resolving was completed. time_connect The time, in seconds, it took from the start until the connect to the remote host (or proxy) was completed. time_pretransfer The time, in seconds, it took from the start until the file transfer is just about to begin. This includes all pre-transfer commands and nego- tiations that are specific to the particular pro- tocol(s) involved. time_redirect The time, in seconds, it took for all redirection steps include name lookup, connect, pretransfer and transfer before final transaction was started. time_redirect shows the complete execu- tion time for multiple redirections. (Added in 7.12.3) time_starttransfer The time, in seconds, it took from the start until the first byte is just about to be trans- ferred. This includes time_pretransfer and also the time the server needs to calculate the result. size_download The total amount of bytes that were downloaded. size_upload The total amount of bytes that were uploaded. size_header The total amount of bytes of the downloaded head- ers. size_request The total amount of bytes that were sent in the HTTP request. speed_download The average download speed that curl measured for the complete download. speed_upload The average upload speed that curl measured for the complete upload. content_type The Content-Type of the requested document, if there was any. (Added in 7.9.5) 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) If this option is used several times, the last one will be used. -x/--proxy Use specified HTTP proxy. If the port number is not specified, it is assumed at port 1080. This option overrides existing environment variables that sets proxy to use. If there's an environment variable setting a proxy, you can set proxy to "" to override it. Note that all operations that are performed over a HTTP proxy will transparently be converted to HTTP. It means that certain protocol specific operations might not be available. This is not the case if you can tunnel through the proxy, as done with the -p/--proxytunnel option. If this option is used several times, the last one will be used. -X/--request (HTTP) Specifies a custom request to use when communicating with the HTTP server. The specified request will be used instead of the standard GET. Read the HTTP 1.1 specification for details and explanations. (FTP) Specifies a custom FTP command to use instead of LIST when doing file lists with ftp. If this option is used several times, the last one will be used. -y/--speed-time