3 You always find news about what's going on as well as the latest versions
4 from the curl web pages, located at:
10 Get the main page from Netscape's web-server:
12 curl http://www.netscape.com/
14 Get the README file the user's home directory at funet's ftp-server:
16 curl ftp://ftp.funet.fi/README
18 Get a web page from a server using port 8000:
20 curl http://www.weirdserver.com:8000/
22 Get a directory listing of an FTP site:
24 curl ftp://cool.haxx.se/
26 Get the definition of curl from a dictionary:
28 curl dict://dict.org/m:curl
30 Fetch two documents at once:
32 curl ftp://cool.haxx.se/ http://www.weirdserver.com:8000/
34 Get a file off an FTPS server:
36 curl ftps://files.are.secure.com/secrets.txt
38 or use the more appropriate FTPS way to get the same file:
40 curl --ftp-ssl ftp://files.are.secure.com/secrets.txt
42 Get a file from an SSH server using SFTP:
44 curl -u username sftp://example.com/etc/issue
46 Get a file from an SSH server using SCP using a private key
47 (not password-protected) to authenticate:
49 curl -u username: --key ~/.ssh/id_rsa \
50 scp://example.com/~/file.txt
52 Get a file from an SSH server using SCP using a private key
53 (password-protected) to authenticate:
55 curl -u username: --key ~/.ssh/id_rsa --pass private_key_password \
56 scp://example.com/~/file.txt
58 Get the main page from an IPv6 web server:
60 curl "http://[2001:1890:1112:1::20]/"
62 Get a file from an SMB server:
64 curl -u "domain\username:passwd" smb://server.example.com/share/file.txt
68 Get a web page and store in a local file with a specific name:
70 curl -o thatpage.html http://www.netscape.com/
72 Get a web page and store in a local file, make the local file get the name
73 of the remote document (if no file name part is specified in the URL, this
76 curl -O http://www.netscape.com/index.html
78 Fetch two files and store them with their remote names:
80 curl -O www.haxx.se/index.html -O curl.haxx.se/download.html
86 To ftp files using name+passwd, include them in the URL like:
88 curl ftp://name:passwd@machine.domain:port/full/path/to/file
90 or specify them with the -u flag like
92 curl -u name:passwd ftp://machine.domain:port/full/path/to/file
96 It is just like for FTP, but you may also want to specify and use
97 SSL-specific options for certificates etc.
99 Note that using FTPS:// as prefix is the "implicit" way as described in the
100 standards while the recommended "explicit" way is done by using FTP:// and
101 the --ftp-ssl option.
105 This is similar to FTP, but you can use the --key option to specify a
106 private key to use instead of a password. Note that the private key may
107 itself be protected by a password that is unrelated to the login password
108 of the remote system; this password is specified using the --pass option.
109 Typically, curl will automatically extract the public key from the private
110 key file, but in cases where curl does not have the proper library support,
111 a matching public key file must be specified using the --pubkey option.
115 Curl also supports user and password in HTTP URLs, thus you can pick a file
118 curl http://name:passwd@machine.domain/full/path/to/file
120 or specify user and password separately like in
122 curl -u name:passwd http://machine.domain/full/path/to/file
124 HTTP offers many different methods of authentication and curl supports
125 several: Basic, Digest, NTLM and Negotiate (SPNEGO). Without telling which
126 method to use, curl defaults to Basic. You can also ask curl to pick the
127 most secure ones out of the ones that the server accepts for the given URL,
130 NOTE! According to the URL specification, HTTP URLs can not contain a user
131 and password, so that style will not work when using curl via a proxy, even
132 though curl allows it at other times. When using a proxy, you _must_ use
133 the -u style for user and password.
137 Probably most commonly used with private certificates, as explained below.
141 curl supports both HTTP and SOCKS proxy servers, with optional authentication.
142 It does not have special support for FTP proxy servers since there are no
143 standards for those, but it can still be made to work with many of them. You
144 can also use both HTTP and SOCKS proxies to transfer files to and from FTP
147 Get an ftp file using an HTTP proxy named my-proxy that uses port 888:
149 curl -x my-proxy:888 ftp://ftp.leachsite.com/README
151 Get a file from an HTTP server that requires user and password, using the
154 curl -u user:passwd -x my-proxy:888 http://www.get.this/
156 Some proxies require special authentication. Specify by using -U as above:
158 curl -U user:passwd -x my-proxy:888 http://www.get.this/
160 A comma-separated list of hosts and domains which do not use the proxy can
163 curl --noproxy localhost,get.this -x my-proxy:888 http://www.get.this/
165 If the proxy is specified with --proxy1.0 instead of --proxy or -x, then
166 curl will use HTTP/1.0 instead of HTTP/1.1 for any CONNECT attempts.
168 curl also supports SOCKS4 and SOCKS5 proxies with --socks4 and --socks5.
170 See also the environment variables Curl supports that offer further proxy
173 Most FTP proxy servers are set up to appear as a normal FTP server from the
174 client's perspective, with special commands to select the remote FTP server.
175 curl supports the -u, -Q and --ftp-account options that can be used to
176 set up transfers through many FTP proxies. For example, a file can be
177 uploaded to a remote FTP server using a Blue Coat FTP proxy with the
180 curl -u "Remote-FTP-Username@remote.ftp.server Proxy-Username:Remote-Pass" \
181 --ftp-account Proxy-Password --upload-file local-file \
182 ftp://my-ftp.proxy.server:21/remote/upload/path/
184 See the manual for your FTP proxy to determine the form it expects to set up
185 transfers, and curl's -v option to see exactly what curl is sending.
189 HTTP 1.1 introduced byte-ranges. Using this, a client can request
190 to get only one or more subparts of a specified document. Curl supports
191 this with the -r flag.
193 Get the first 100 bytes of a document:
195 curl -r 0-99 http://www.get.this/
197 Get the last 500 bytes of a document:
199 curl -r -500 http://www.get.this/
201 Curl also supports simple ranges for FTP files as well. Then you can only
202 specify start and stop position.
204 Get the first 100 bytes of a document using FTP:
206 curl -r 0-99 ftp://www.get.this/README
210 FTP / FTPS / SFTP / SCP
212 Upload all data on stdin to a specified server:
214 curl -T - ftp://ftp.upload.com/myfile
216 Upload data from a specified file, login with user and password:
218 curl -T uploadfile -u user:passwd ftp://ftp.upload.com/myfile
220 Upload a local file to the remote site, and use the local file name at the remote
223 curl -T uploadfile -u user:passwd ftp://ftp.upload.com/
225 Upload a local file to get appended to the remote file:
227 curl -T localfile -a ftp://ftp.upload.com/remotefile
229 Curl also supports ftp upload through a proxy, but only if the proxy is
230 configured to allow that kind of tunneling. If it does, you can run curl in
231 a fashion similar to:
233 curl --proxytunnel -x proxy:port -T localfile ftp.upload.com
237 curl -T file.txt -u "domain\username:passwd"
238 smb://server.example.com/share/
242 Upload all data on stdin to a specified HTTP site:
244 curl -T - http://www.upload.com/myfile
246 Note that the HTTP server must have been configured to accept PUT before
247 this can be done successfully.
249 For other ways to do HTTP data upload, see the POST section below.
253 If curl fails where it isn't supposed to, if the servers don't let you in,
254 if you can't understand the responses: use the -v flag to get verbose
255 fetching. Curl will output lots of info and what it sends and receives in
256 order to let the user see all client-server interaction (but it won't show
257 you the actual data).
259 curl -v ftp://ftp.upload.com/
261 To get even more details and information on what curl does, try using the
262 --trace or --trace-ascii options with a given file name to log to, like
265 curl --trace trace.txt www.haxx.se
270 Different protocols provide different ways of getting detailed information
271 about specific files/documents. To get curl to show detailed information
272 about a single file, you should use -I/--head option. It displays all
273 available info on a single file for HTTP and FTP. The HTTP information is a
276 For HTTP, you can get the header information (the same as -I would show)
277 shown before the data by using -i/--include. Curl understands the
278 -D/--dump-header option when getting files from both FTP and HTTP, and it
279 will then store the headers in the specified file.
281 Store the HTTP headers in a separate file (headers.txt in the example):
283 curl --dump-header headers.txt curl.haxx.se
285 Note that headers stored in a separate file can be very useful at a later
286 time if you want curl to use cookies sent by the server. More about that in
291 It's easy to post data using curl. This is done using the -d <data>
292 option. The post data must be urlencoded.
294 Post a simple "name" and "phone" guestbook.
296 curl -d "name=Rafael%20Sagula&phone=3320780" \
297 http://www.where.com/guest.cgi
299 How to post a form with curl, lesson #1:
301 Dig out all the <input> tags in the form that you want to fill in. (There's
302 a perl program called formfind.pl on the curl site that helps with this).
304 If there's a "normal" post, you use -d to post. -d takes a full "post
305 string", which is in the format
307 <variable1>=<data1>&<variable2>=<data2>&...
309 The 'variable' names are the names set with "name=" in the <input> tags, and
310 the data is the contents you want to fill in for the inputs. The data *must*
311 be properly URL encoded. That means you replace space with + and that you
312 replace weird letters with %XX where XX is the hexadecimal representation of
313 the letter's ASCII code.
317 (page located at http://www.formpost.com/getthis/
319 <form action="post.cgi" method="post">
320 <input name=user size=10>
321 <input name=pass type=password size=10>
322 <input name=id type=hidden value="blablabla">
323 <input name=ding value="submit">
326 We want to enter user 'foobar' with password '12345'.
328 To post to this, you enter a curl command line like:
330 curl -d "user=foobar&pass=12345&id=blablabla&ding=submit" (continues)
331 http://www.formpost.com/getthis/post.cgi
334 While -d uses the application/x-www-form-urlencoded mime-type, generally
335 understood by CGI's and similar, curl also supports the more capable
336 multipart/form-data type. This latter type supports things like file upload.
338 -F accepts parameters like -F "name=contents". If you want the contents to
339 be read from a file, use <@filename> as contents. When specifying a file,
340 you can also specify the file content type by appending ';type=<mime type>'
341 to the file name. You can also post the contents of several files in one
342 field. For example, the field name 'coolfiles' is used to send three files,
343 with different content types using the following syntax:
345 curl -F "coolfiles=@fil1.gif;type=image/gif,fil2.txt,fil3.html" \
346 http://www.post.com/postit.cgi
348 If the content-type is not specified, curl will try to guess from the file
349 extension (it only knows a few), or use the previously specified type (from
350 an earlier file if several files are specified in a list) or else it will
351 use the default type 'application/octet-stream'.
353 Emulate a fill-in form with -F. Let's say you fill in three fields in a
354 form. One field is a file name which to post, one field is your name and one
355 field is a file description. We want to post the file we have written named
356 "cooltext.txt". To let curl do the posting of this data instead of your
357 favourite browser, you have to read the HTML source of the form page and
358 find the names of the input fields. In our example, the input field names
359 are 'file', 'yourname' and 'filedescription'.
361 curl -F "file=@cooltext.txt" -F "yourname=Daniel" \
362 -F "filedescription=Cool text file with cool text inside" \
363 http://www.post.com/postit.cgi
365 To send two files in one post you can do it in two ways:
367 1. Send multiple files in a single "field" with a single field name:
369 curl -F "pictures=@dog.gif,cat.gif"
371 2. Send two fields with two field names:
373 curl -F "docpicture=@dog.gif" -F "catpicture=@cat.gif"
375 To send a field value literally without interpreting a leading '@'
376 or '<', or an embedded ';type=', use --form-string instead of
377 -F. This is recommended when the value is obtained from a user or
378 some other unpredictable source. Under these circumstances, using
379 -F instead of --form-string would allow a user to trick curl into
384 An HTTP request has the option to include information about which address
385 referred it to the actual page. Curl allows you to specify the
386 referrer to be used on the command line. It is especially useful to
387 fool or trick stupid servers or CGI scripts that rely on that information
388 being available or contain certain data.
390 curl -e www.coolsite.com http://www.showme.com/
392 NOTE: The Referer: [sic] field is defined in the HTTP spec to be a full URL.
396 An HTTP request has the option to include information about the browser
397 that generated the request. Curl allows it to be specified on the command
398 line. It is especially useful to fool or trick stupid servers or CGI
399 scripts that only accept certain browsers.
403 curl -A 'Mozilla/3.0 (Win95; I)' http://www.nationsbank.com/
405 Other common strings:
406 'Mozilla/3.0 (Win95; I)' Netscape Version 3 for Windows 95
407 'Mozilla/3.04 (Win95; U)' Netscape Version 3 for Windows 95
408 'Mozilla/2.02 (OS/2; U)' Netscape Version 2 for OS/2
409 'Mozilla/4.04 [en] (X11; U; AIX 4.2; Nav)' NS for AIX
410 'Mozilla/4.05 [en] (X11; U; Linux 2.0.32 i586)' NS for Linux
412 Note that Internet Explorer tries hard to be compatible in every way:
413 'Mozilla/4.0 (compatible; MSIE 4.01; Windows 95)' MSIE for W95
415 Mozilla is not the only possible User-Agent name:
416 'Konqueror/1.0' KDE File Manager desktop client
417 'Lynx/2.7.1 libwww-FM/2.14' Lynx command line browser
421 Cookies are generally used by web servers to keep state information at the
422 client's side. The server sets cookies by sending a response line in the
423 headers that looks like 'Set-Cookie: <data>' where the data part then
424 typically contains a set of NAME=VALUE pairs (separated by semicolons ';'
425 like "NAME1=VALUE1; NAME2=VALUE2;"). The server can also specify for what
426 path the "cookie" should be used for (by specifying "path=value"), when the
427 cookie should expire ("expire=DATE"), for what domain to use it
428 ("domain=NAME") and if it should be used on secure connections only
431 If you've received a page from a server that contains a header like:
432 Set-Cookie: sessionid=boo123; path="/foo";
434 it means the server wants that first pair passed on when we get anything in
435 a path beginning with "/foo".
437 Example, get a page that wants my name passed in a cookie:
439 curl -b "name=Daniel" www.sillypage.com
441 Curl also has the ability to use previously received cookies in following
442 sessions. If you get cookies from a server and store them in a file in a
445 curl --dump-header headers www.example.com
447 ... you can then in a second connect to that (or another) site, use the
448 cookies from the 'headers' file like:
450 curl -b headers www.example.com
452 While saving headers to a file is a working way to store cookies, it is
453 however error-prone and not the preferred way to do this. Instead, make curl
454 save the incoming cookies using the well-known netscape cookie format like
457 curl -c cookies.txt www.example.com
459 Note that by specifying -b you enable the "cookie awareness" and with -L
460 you can make curl follow a location: (which often is used in combination
461 with cookies). So that if a site sends cookies and a location, you can
462 use a non-existing file to trigger the cookie awareness like:
464 curl -L -b empty.txt www.example.com
466 The file to read cookies from must be formatted using plain HTTP headers OR
467 as netscape's cookie file. Curl will determine what kind it is based on the
468 file contents. In the above command, curl will parse the header and store
469 the cookies received from www.example.com. curl will send to the server the
470 stored cookies which match the request as it follows the location. The
471 file "empty.txt" may be a nonexistent file.
473 To read and write cookies from a netscape cookie file, you can set both -b
474 and -c to use the same file:
476 curl -b cookies.txt -c cookies.txt www.example.com
480 The progress meter exists to show a user that something actually is
481 happening. The different fields in the output have the following meaning:
483 % Total % Received % Xferd Average Speed Time Curr.
484 Dload Upload Total Current Left Speed
485 0 151M 0 38608 0 0 9406 0 4:41:43 0:00:04 4:41:39 9287
488 % - percentage completed of the whole transfer
489 Total - total size of the whole expected transfer
490 % - percentage completed of the download
491 Received - currently downloaded amount of bytes
492 % - percentage completed of the upload
493 Xferd - currently uploaded amount of bytes
495 Dload - the average transfer speed of the download
497 Upload - the average transfer speed of the upload
498 Time Total - expected time to complete the operation
499 Time Current - time passed since the invoke
500 Time Left - expected time left to completion
501 Curr.Speed - the average transfer speed the last 5 seconds (the first
502 5 seconds of a transfer is based on less time of course.)
504 The -# option will display a totally different progress bar that doesn't
505 need much explanation!
509 Curl allows the user to set the transfer speed conditions that must be met
510 to let the transfer keep going. By using the switch -y and -Y you
511 can make curl abort transfers if the transfer speed is below the specified
512 lowest limit for a specified time.
514 To have curl abort the download if the speed is slower than 3000 bytes per
515 second for 1 minute, run:
517 curl -Y 3000 -y 60 www.far-away-site.com
519 This can very well be used in combination with the overall time limit, so
520 that the above operation must be completed in whole within 30 minutes:
522 curl -m 1800 -Y 3000 -y 60 www.far-away-site.com
524 Forcing curl not to transfer data faster than a given rate is also possible,
525 which might be useful if you're using a limited bandwidth connection and you
526 don't want your transfer to use all of it (sometimes referred to as
527 "bandwidth throttle").
529 Make curl transfer data no faster than 10 kilobytes per second:
531 curl --limit-rate 10K www.far-away-site.com
535 curl --limit-rate 10240 www.far-away-site.com
537 Or prevent curl from uploading data faster than 1 megabyte per second:
539 curl -T upload --limit-rate 1M ftp://uploadshereplease.com
541 When using the --limit-rate option, the transfer rate is regulated on a
542 per-second basis, which will cause the total transfer speed to become lower
543 than the given number. Sometimes of course substantially lower, if your
544 transfer stalls during periods.
548 Curl automatically tries to read the .curlrc file (or _curlrc file on win32
549 systems) from the user's home dir on startup.
551 The config file could be made up with normal command line switches, but you
552 can also specify the long options without the dashes to make it more
553 readable. You can separate the options and the parameter with spaces, or
554 with = or :. Comments can be used within the file. If the first letter on a
555 line is a '#'-symbol the rest of the line is treated as a comment.
557 If you want the parameter to contain spaces, you must enclose the entire
558 parameter within double quotes ("). Within those quotes, you specify a
561 NOTE: You must specify options and their arguments on the same line.
563 Example, set default time out and proxy in a config file:
565 # We want a 30 minute timeout:
567 # ... and we use a proxy for all accesses:
568 proxy = proxy.our.domain.com:8080
570 White spaces ARE significant at the end of lines, but all white spaces
571 leading up to the first characters of each line are ignored.
573 Prevent curl from reading the default file by using -q as the first command
574 line parameter, like:
576 curl -q www.thatsite.com
578 Force curl to get and display a local help page in case it is invoked
579 without URL by making a config file similar to:
582 url = "http://help.with.curl.com/curlhelp.html"
584 You can specify another config file to be read by using the -K/--config
585 flag. If you set config file name to "-" it'll read the config from stdin,
586 which can be handy if you want to hide options from being visible in process
589 echo "user = user:passwd" | curl -K - http://that.secret.site.com
593 When using curl in your own very special programs, you may end up needing
594 to pass on your own custom headers when getting a web page. You can do
595 this by using the -H flag.
597 Example, send the header "X-you-and-me: yes" to the server when getting a
600 curl -H "X-you-and-me: yes" www.love.com
602 This can also be useful in case you want curl to send a different text in a
603 header than it normally does. The -H header you specify then replaces the
604 header curl would normally send. If you replace an internal header with an
605 empty one, you prevent that header from being sent. To prevent the Host:
606 header from being used:
608 curl -H "Host:" www.server.com
612 Do note that when getting files with the ftp:// URL, the given path is
613 relative the directory you enter. To get the file 'README' from your home
614 directory at your ftp site, do:
616 curl ftp://user:passwd@my.site.com/README
618 But if you want the README file from the root directory of that very same
619 site, you need to specify the absolute file name:
621 curl ftp://user:passwd@my.site.com//README
623 (I.e with an extra slash in front of the file name.)
625 SFTP and SCP and PATH NAMES
627 With sftp: and scp: URLs, the path name given is the absolute name on the
628 server. To access a file relative to the remote user's home directory,
629 prefix the file with /~/ , such as:
631 curl -u $USER sftp://home.example.com/~/.bashrc
635 The FTP protocol requires one of the involved parties to open a second
636 connection as soon as data is about to get transferred. There are two ways to
639 The default way for curl is to issue the PASV command which causes the
640 server to open another port and await another connection performed by the
641 client. This is good if the client is behind a firewall that doesn't allow
642 incoming connections.
644 curl ftp.download.com
646 If the server, for example, is behind a firewall that doesn't allow connections
647 on ports other than 21 (or if it just doesn't support the PASV command), the
648 other way to do it is to use the PORT command and instruct the server to
649 connect to the client on the given IP number and port (as parameters to the
652 The -P flag to curl supports a few different options. Your machine may have
653 several IP-addresses and/or network interfaces and curl allows you to select
654 which of them to use. Default address can also be used:
656 curl -P - ftp.download.com
658 Download with PORT but use the IP address of our 'le0' interface (this does
659 not work on windows):
661 curl -P le0 ftp.download.com
663 Download with PORT but use 192.168.0.10 as our IP address to use:
665 curl -P 192.168.0.10 ftp.download.com
669 Get a web page from a server using a specified port for the interface:
671 curl --interface eth0:1 http://www.netscape.com/
675 curl --interface 192.168.1.10 http://www.netscape.com/
679 Secure HTTP requires SSL libraries to be installed and used when curl is
680 built. If that is done, curl is capable of retrieving and posting documents
681 using the HTTPS protocol.
685 curl https://www.secure-site.com
687 Curl is also capable of using your personal certificates to get/post files
688 from sites that require valid certificates. The only drawback is that the
689 certificate needs to be in PEM-format. PEM is a standard and open format to
690 store certificates with, but it is not used by the most commonly used
691 browsers (Netscape and MSIE both use the so called PKCS#12 format). If you
692 want curl to use the certificates you use with your (favourite) browser, you
693 may need to download/compile a converter that can convert your browser's
694 formatted certificates to PEM formatted ones. This kind of converter is
695 included in recent versions of OpenSSL, and for older versions Dr Stephen
696 N. Henson has written a patch for SSLeay that adds this functionality. You
697 can get his patch (that requires an SSLeay installation) from his site at:
698 http://www.drh-consultancy.demon.co.uk/
700 Example on how to automatically retrieve a document using a certificate with
703 curl -E /path/to/cert.pem:password https://secure.site.com/
705 If you neglect to specify the password on the command line, you will be
706 prompted for the correct password before any data can be received.
708 Many older SSL-servers have problems with SSLv3 or TLS, which newer versions
709 of OpenSSL etc use, therefore it is sometimes useful to specify what
710 SSL-version curl should use. Use -3, -2 or -1 to specify that exact SSL
711 version to use (for SSLv3, SSLv2 or TLSv1 respectively):
713 curl -2 https://secure.site.com/
715 Otherwise, curl will first attempt to use v3 and then v2.
717 To use OpenSSL to convert your favourite browser's certificate into a PEM
718 formatted one that curl can use, do something like this:
720 In Netscape, you start with hitting the 'Security' menu button.
722 Select 'certificates->yours' and then pick a certificate in the list
724 Press the 'Export' button
726 enter your PIN code for the certs
728 select a proper place to save it
730 Run the 'openssl' application to convert the certificate. If you cd to the
731 openssl installation, you can do it like:
733 # ./apps/openssl pkcs12 -in [file you saved] -clcerts -out [PEMfile]
735 In Firefox, select Options, then Advanced, then the Encryption tab,
736 View Certificates. This opens the Certificate Manager, where you can
737 Export. Be sure to select PEM for the Save as type.
739 In Internet Explorer, select Internet Options, then the Content tab, then
740 Certificates. Then you can Export, and depending on the format you may
741 need to convert to PEM.
743 In Chrome, select Settings, then Show Advanced Settings. Under HTTPS/SSL
744 select Manage Certificates.
746 RESUMING FILE TRANSFERS
748 To continue a file transfer where it was previously aborted, curl supports
749 resume on HTTP(S) downloads as well as FTP uploads and downloads.
751 Continue downloading a document:
753 curl -C - -o file ftp://ftp.server.com/path/file
755 Continue uploading a document(*1):
757 curl -C - -T file ftp://ftp.server.com/path/file
759 Continue downloading a document from a web server(*2):
761 curl -C - -o file http://www.server.com/
763 (*1) = This requires that the FTP server supports the non-standard command
764 SIZE. If it doesn't, curl will say so.
766 (*2) = This requires that the web server supports at least HTTP/1.1. If it
767 doesn't, curl will say so.
771 HTTP allows a client to specify a time condition for the document it
772 requests. It is If-Modified-Since or If-Unmodified-Since. Curl allows you to
773 specify them with the -z/--time-cond flag.
775 For example, you can easily make a download that only gets performed if the
776 remote file is newer than a local copy. It would be made like:
778 curl -z local.html http://remote.server.com/remote.html
780 Or you can download a file only if the local file is newer than the remote
781 one. Do this by prepending the date string with a '-', as in:
783 curl -z -local.html http://remote.server.com/remote.html
785 You can specify a "free text" date as condition. Tell curl to only download
786 the file if it was updated since January 12, 2012:
788 curl -z "Jan 12 2012" http://remote.server.com/remote.html
790 Curl will then accept a wide range of date formats. You always make the date
791 check the other way around by prepending it with a dash '-'.
797 curl dict://dict.org/m:curl
798 curl dict://dict.org/d:heisenbug:jargon
799 curl dict://dict.org/d:daniel:web1913
801 Aliases for 'm' are 'match' and 'find', and aliases for 'd' are 'define'
802 and 'lookup'. For example,
804 curl dict://dict.org/find:curl
806 Commands that break the URL description of the RFC (but not the DICT
809 curl dict://dict.org/show:db
810 curl dict://dict.org/show:strat
812 Authentication is still missing (but this is not required by the RFC)
816 If you have installed the OpenLDAP library, curl can take advantage of it
817 and offer ldap:// support.
818 On Windows, curl will use WinLDAP from Platform SDK by default.
820 Default protocol version used by curl is LDAPv3. LDAPv2 will be used as
821 fallback mechanism in case if LDAPv3 will fail to connect.
823 LDAP is a complex thing and writing an LDAP query is not an easy task. I do
824 advise you to dig up the syntax description for that elsewhere. One such
827 RFC 2255, "The LDAP URL Format" https://curl.haxx.se/rfc/rfc2255.txt
829 To show you an example, this is how I can get all people from my local LDAP
830 server that has a certain sub-domain in their email address:
832 curl -B "ldap://ldap.frontec.se/o=frontec??sub?mail=*sth.frontec.se"
834 If I want the same info in HTML format, I can get it by not using the -B
835 (enforce ASCII) flag.
837 You also can use authentication when accessing LDAP catalog:
839 curl -u user:passwd "ldap://ldap.frontec.se/o=frontec??sub?mail=*"
840 curl "ldap://user:passwd@ldap.frontec.se/o=frontec??sub?mail=*"
842 By default, if user and password provided, OpenLDAP/WinLDAP will use basic
843 authentication. On Windows you can control this behavior by providing
844 one of --basic, --ntlm or --digest option in curl command line
846 curl --ntlm "ldap://user:passwd@ldap.frontec.se/o=frontec??sub?mail=*"
848 On Windows, if no user/password specified, auto-negotiation mechanism will
849 be used with current logon credentials (SSPI/SPNEGO).
851 ENVIRONMENT VARIABLES
853 Curl reads and understands the following environment variables:
855 http_proxy, HTTPS_PROXY, FTP_PROXY
857 They should be set for protocol-specific proxies. General proxy should be
862 A comma-separated list of host names that shouldn't go through any proxy is
863 set in (only an asterisk, '*' matches all hosts)
867 If the host name matches one of these strings, or the host is within the
868 domain of one of these strings, transactions with that node will not be
869 proxied. When a domain is used, it needs to start with a period. A user can
870 specify that both www.example.com and foo.example.com should not uses a
871 proxy by setting NO_PROXY to ".example.com". By including the full name you
872 can exclude specific host names, so to make www.example.com not use a proxy
873 but still have foo.example.com do it, set NO_PROXY to "www.example.com"
875 The usage of the -x/--proxy flag overrides the environment variables.
879 Unix introduced the .netrc concept a long time ago. It is a way for a user
880 to specify name and password for commonly visited FTP sites in a file so
881 that you don't have to type them in each time you visit those sites. You
882 realize this is a big security risk if someone else gets hold of your
883 passwords, so therefore most unix programs won't read this file unless it is
884 only readable by yourself (curl doesn't care though).
886 Curl supports .netrc files if told to (using the -n/--netrc and
887 --netrc-optional options). This is not restricted to just FTP,
888 so curl can use it for all protocols where authentication is used.
890 A very simple .netrc file could look something like:
892 machine curl.haxx.se login iamdaniel password mysecret
896 To better allow script programmers to get to know about the progress of
897 curl, the -w/--write-out option was introduced. Using this, you can specify
898 what information from the previous transfer you want to extract.
900 To display the amount of bytes downloaded together with some text and an
903 curl -w 'We downloaded %{size_download} bytes\n' www.download.com
905 KERBEROS FTP TRANSFER
907 Curl supports kerberos4 and kerberos5/GSSAPI for FTP transfers. You need
908 the kerberos package installed and used at curl build time for it to be
911 First, get the krb-ticket the normal way, like with the kinit/kauth tool.
912 Then use curl in way similar to:
914 curl --krb private ftp://krb4site.com -u username:fakepwd
916 There's no use for a password on the -u switch, but a blank one will make
917 curl ask for one and you already entered the real password to kinit/kauth.
921 The curl telnet support is basic and very easy to use. Curl passes all data
922 passed to it on stdin to the remote server. Connect to a remote telnet
923 server using a command line similar to:
925 curl telnet://remote.server.com
927 And enter the data to pass to the server on stdin. The result will be sent
928 to stdout or to the file you specify with -o.
930 You might want the -N/--no-buffer option to switch off the buffered output
931 for slow connections or similar.
933 Pass options to the telnet protocol negotiation, by using the -t option. To
934 tell the server we use a vt100 terminal, try something like:
936 curl -tTTYPE=vt100 telnet://remote.server.com
938 Other interesting options for it -t include:
940 - XDISPLOC=<X display> Sets the X display location.
942 - NEW_ENV=<var,val> Sets an environment variable.
944 NOTE: The telnet protocol does not specify any way to login with a specified
945 user and password so curl can't do that automatically. To do that, you need
946 to track when the login prompt is received and send the username and
947 password accordingly.
949 PERSISTENT CONNECTIONS
951 Specifying multiple files on a single command line will make curl transfer
952 all of them, one after the other in the specified order.
954 libcurl will attempt to use persistent connections for the transfers so that
955 the second transfer to the same host can use the same connection that was
956 already initiated and was left open in the previous transfer. This greatly
957 decreases connection time for all but the first transfer and it makes a far
958 better use of the network.
960 Note that curl cannot use persistent connections for transfers that are used
961 in subsequence curl invokes. Try to stuff as many URLs as possible on the
962 same command line if they are using the same host, as that'll make the
963 transfers faster. If you use an HTTP proxy for file transfers, practically
964 all transfers will be persistent.
966 MULTIPLE TRANSFERS WITH A SINGLE COMMAND LINE
968 As is mentioned above, you can download multiple files with one command line
969 by simply adding more URLs. If you want those to get saved to a local file
970 instead of just printed to stdout, you need to add one save option for each
971 URL you specify. Note that this also goes for the -O option (but not
974 For example: get two files and use -O for the first and a custom file
977 curl -O http://url.com/file.txt ftp://ftp.com/moo.exe -o moo.jpg
979 You can also upload multiple files in a similar fashion:
981 curl -T local1 ftp://ftp.com/moo.exe -T local2 ftp://ftp.com/moo2.txt
985 curl will connect to a server with IPv6 when a host lookup returns an IPv6
986 address and fall back to IPv4 if the connection fails. The --ipv4 and --ipv6
987 options can specify which address to use when both are available. IPv6
988 addresses can also be specified directly in URLs using the syntax:
990 http://[2001:1890:1112:1::20]/overview.html
992 When this style is used, the -g option must be given to stop curl from
993 interpreting the square brackets as special globbing characters. Link local
994 and site local addresses including a scope identifier, such as fe80::1234%1,
995 may also be used, but the scope portion must be numeric or match an existing
996 network interface on Linux and the percent character must be URL escaped. The
997 previous example in an SFTP URL might look like:
999 sftp://[fe80::1234%251]/
1001 IPv6 addresses provided other than in URLs (e.g. to the --proxy, --interface
1002 or --ftp-port options) should not be URL encoded.
1006 Curl supports Metalink (both version 3 and 4 (RFC 5854) are supported), a way
1007 to list multiple URIs and hashes for a file. Curl will make use of the mirrors
1008 listed within for failover if there are errors (such as the file or server not
1009 being available). It will also verify the hash of the file after the download
1010 completes. The Metalink file itself is downloaded and processed in memory and
1011 not stored in the local file system.
1013 Example to use a remote Metalink file:
1015 curl --metalink http://www.example.com/example.metalink
1017 To use a Metalink file in the local file system, use FILE protocol (file://):
1019 curl --metalink file://example.metalink
1021 Please note that if FILE protocol is disabled, there is no way to use a local
1022 Metalink file at the time of this writing. Also note that if --metalink and
1023 --include are used together, --include will be ignored. This is because including
1024 headers in the response will break Metalink parser and if the headers are included
1025 in the file described in Metalink file, hash check will fail.
1029 For your convenience, we have several open mailing lists to discuss curl,
1030 its development and things relevant to this. Get all info at
1031 https://curl.haxx.se/mail/. Some of the lists available are:
1035 Users of the command line tool. How to use it, what doesn't work, new
1036 features, related tools, questions, news, installations, compilations,
1037 running, porting etc.
1041 Developers using or developing libcurl. Bugs, extensions, improvements.
1045 Low-traffic. Only receives announcements of new public versions. At worst,
1046 that makes something like one or two mails per month, but usually only one
1047 mail every second month.
1051 Using the curl functions in PHP. Everything curl with a PHP angle. Or PHP
1056 Python hackers using curl with or without the python binding pycurl.
1058 Please direct curl questions, feature requests and trouble reports to one of
1059 these mailing lists instead of mailing any individual.