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 root README file from funet's ftp-server:
16 curl ftp://ftp.funet.fi/README
18 Get a gopher document from funet's gopher server:
20 curl gopher://gopher.funet.fi
22 Get a web page from a server using port 8000:
24 curl http://www.weirdserver.com:8000/
26 Get a list of the root directory of an FTP site:
28 curl ftp://ftp.fts.frontec.se/
30 Get the definition of curl from a dictionary:
32 curl dict://dict.org/m:curl
36 Get a web page and store in a local file:
38 curl -o thatpage.html http://www.netscape.com/
40 Get a web page and store in a local file, make the local file get the name
41 of the remote document (if no file name part is specified in the URL, this
44 curl -O http://www.netscape.com/index.html
50 To ftp files using name+passwd, include them in the URL like:
52 curl ftp://name:passwd@machine.domain:port/full/path/to/file
54 or specify them with the -u flag like
56 curl -u name:passwd ftp://machine.domain:port/full/path/to/file
60 The HTTP URL doesn't support user and password in the URL string. Curl
61 does support that anyway to provide a ftp-style interface and thus you can
64 curl http://name:passwd@machine.domain/full/path/to/file
66 or specify user and password separately like in
68 curl -u name:passwd http://machine.domain/full/path/to/file
70 NOTE! Since HTTP URLs don't support user and password, you can't use that
71 style when using Curl via a proxy. You _must_ use the -u style fetch
72 during such circumstances.
76 Probably most commonly used with private certificates, as explained below.
80 Curl features no password support for gopher.
84 Get an ftp file using a proxy named my-proxy that uses port 888:
86 curl -x my-proxy:888 ftp://ftp.leachsite.com/README
88 Get a file from a HTTP server that requires user and password, using the
91 curl -u user:passwd -x my-proxy:888 http://www.get.this/
93 Some proxies require special authentication. Specify by using -U as above:
95 curl -U user:passwd -x my-proxy:888 http://www.get.this/
97 See also the environment variables Curl support that offer further proxy
102 With HTTP 1.1 byte-ranges were introduced. Using this, a client can request
103 to get only one or more subparts of a specified document. Curl supports
104 this with the -r flag.
106 Get the first 100 bytes of a document:
108 curl -r 0-99 http://www.get.this/
110 Get the last 500 bytes of a document:
112 curl -r -500 http://www.get.this/
114 Curl also supports simple ranges for FTP files as well. Then you can only
115 specify start and stop position.
117 Get the first 100 bytes of a document using FTP:
119 curl -r 0-99 ftp://www.get.this/README
125 Upload all data on stdin to a specified ftp site:
127 curl -t ftp://ftp.upload.com/myfile
129 Upload data from a specified file, login with user and password:
131 curl -T uploadfile -u user:passwd ftp://ftp.upload.com/myfile
133 Upload a local file to the remote site, and use the local file name remote
136 curl -T uploadfile -u user:passwd ftp://ftp.upload.com/
138 Upload a local file to get appended to the remote file using ftp:
140 curl -T localfile -a ftp://ftp.upload.com/remotefile
142 Curl also supports ftp upload through a proxy, but only if the proxy is
143 configured to allow that kind of tunneling. If it does, you can run curl in
144 a fashion similar to:
146 curl --proxytunnel -x proxy:port -T localfile ftp.upload.com
150 Upload all data on stdin to a specified http site:
152 curl -t http://www.upload.com/myfile
154 Note that the http server must've been configured to accept PUT before this
155 can be done successfully.
157 For other ways to do http data upload, see the POST section below.
161 If curl fails where it isn't supposed to, if the servers don't let you
162 in, if you can't understand the responses: use the -v flag to get VERBOSE
163 fetching. Curl will output lots of info and all data it sends and
164 receives in order to let the user see all client-server interaction.
166 curl -v ftp://ftp.upload.com/
170 Different protocols provide different ways of getting detailed information
171 about specific files/documents. To get curl to show detailed information
172 about a single file, you should use -I/--head option. It displays all
173 available info on a single file for HTTP and FTP. The HTTP information is a
176 For HTTP, you can get the header information (the same as -I would show)
177 shown before the data by using -i/--include. Curl understands the
178 -D/--dump-header option when getting files from both FTP and HTTP, and it
179 will then store the headers in the specified file.
181 Store the HTTP headers in a separate file:
183 curl --dump-header headers.txt curl.haxx.se
185 Note that headers stored in a separate file can be very useful at a later
186 time if you want curl to use cookies sent by the server. More about that in
191 It's easy to post data using curl. This is done using the -d <data>
192 option. The post data must be urlencoded.
194 Post a simple "name" and "phone" guestbook.
196 curl -d "name=Rafael%20Sagula&phone=3320780" \
197 http://www.where.com/guest.cgi
199 How to post a form with curl, lesson #1:
201 Dig out all the <input> tags in the form that you want to fill in. (There's
202 a perl program called formfind.pl on the curl site that helps with this).
204 If there's a "normal" post, you use -d to post. -d takes a full "post
205 string", which is in the format
207 <variable1>=<data1>&<variable2>=<data2>&...
209 The 'variable' names are the names set with "name=" in the <input> tags, and
210 the data is the contents you want to fill in for the inputs. The data *must*
211 be properly URL encoded. That means you replace space with + and that you
212 write weird letters with %XX where XX is the hexadecimal representation of
213 the letter's ASCII code.
217 (page located at http://www.formpost.com/getthis/
219 <form action="post.cgi" method="post">
220 <input name=user size=10>
221 <input name=pass type=password size=10>
222 <input name=id type=hidden value="blablabla">
223 <input name=ding value="submit">
226 We want to enter user 'foobar' with password '12345'.
228 To post to this, you enter a curl command line like:
230 curl -d "user=foobar&pass=12345&id=blablabla&dig=submit" (continues)
231 http://www.formpost.com/getthis/post.cgi
234 While -d uses the application/x-www-form-urlencoded mime-type, generally
235 understood by CGI's and similar, curl also supports the more capable
236 multipart/form-data type. This latter type supports things like file upload.
238 -F accepts parameters like -F "name=contents". If you want the contents to
239 be read from a file, use <@filename> as contents. When specifying a file,
240 you can also specify which content type the file is, by appending
241 ';type=<mime type>' to the file name. You can also post contents of several
242 files in one field. So that the field name 'coolfiles' can be sent three
243 files with different content types in a manner similar to:
245 curl -F "coolfiles=@fil1.gif;type=image/gif,fil2.txt,fil3.html" \
246 http://www.post.com/postit.cgi
248 If content-type is not specified, curl will try to guess from the extension
249 (it only knows a few), or use the previously specified type (from an earlier
250 file if several files are specified in a list) or finally using the default
253 Emulate a fill-in form with -F. Let's say you fill in three fields in a
254 form. One field is a file name which to post, one field is your name and one
255 field is a file description. We want to post the file we have written named
256 "cooltext.txt". To let curl do the posting of this data instead of your
257 favourite browser, you have to check out the HTML of the form page to get to
258 know the names of the input fields. In our example, the input field names are
259 'file', 'yourname' and 'filedescription'.
261 curl -F "file=@cooltext.txt" -F "yourname=Daniel" \
262 -F "filedescription=Cool text file with cool text inside" \
263 http://www.post.com/postit.cgi
265 So, to send two files in one post you can do it in two ways:
267 1. Send multiple files in a single "field" with a single field name:
269 curl -F "pictures=@dog.gif,cat.gif"
271 2. Send two fields with two field names:
273 curl -F "docpicture=@dog.gif" -F "catpicture=@cat.gif"
277 A HTTP request has the option to include information about which address
278 that referred to actual page, and curl allows the user to specify that
279 referrer to get specified on the command line. It is especially useful to
280 fool or trick stupid servers or CGI scripts that rely on that information
281 being available or contain certain data.
283 curl -e www.coolsite.com http://www.showme.com/
285 NOTE: The referer field is defined in the HTTP spec to be a full URL.
289 A HTTP request has the option to include information about the browser
290 that generated the request. Curl allows it to be specified on the command
291 line. It is especially useful to fool or trick stupid servers or CGI
292 scripts that only accept certain browsers.
296 curl -A 'Mozilla/3.0 (Win95; I)' http://www.nationsbank.com/
298 Other common strings:
299 'Mozilla/3.0 (Win95; I)' Netscape Version 3 for Windows 95
300 'Mozilla/3.04 (Win95; U)' Netscape Version 3 for Windows 95
301 'Mozilla/2.02 (OS/2; U)' Netscape Version 2 for OS/2
302 'Mozilla/4.04 [en] (X11; U; AIX 4.2; Nav)' NS for AIX
303 'Mozilla/4.05 [en] (X11; U; Linux 2.0.32 i586)' NS for Linux
305 Note that Internet Explorer tries hard to be compatible in every way:
306 'Mozilla/4.0 (compatible; MSIE 4.01; Windows 95)' MSIE for W95
308 Mozilla is not the only possible User-Agent name:
309 'Konqueror/1.0' KDE File Manager desktop client
310 'Lynx/2.7.1 libwww-FM/2.14' Lynx command line browser
314 Cookies are generally used by web servers to keep state information at the
315 client's side. The server sets cookies by sending a response line in the
316 headers that looks like 'Set-Cookie: <data>' where the data part then
317 typically contains a set of NAME=VALUE pairs (separated by semicolons ';'
318 like "NAME1=VALUE1; NAME2=VALUE2;"). The server can also specify for what
319 path the "cookie" should be used for (by specifying "path=value"), when the
320 cookie should expire ("expire=DATE"), for what domain to use it
321 ("domain=NAME") and if it should be used on secure connections only
324 If you've received a page from a server that contains a header like:
325 Set-Cookie: sessionid=boo123; path="/foo";
327 it means the server wants that first pair passed on when we get anything in
328 a path beginning with "/foo".
330 Example, get a page that wants my name passed in a cookie:
332 curl -b "name=Daniel" www.sillypage.com
334 Curl also has the ability to use previously received cookies in following
335 sessions. If you get cookies from a server and store them in a file in a
338 curl --dump-header headers www.example.com
340 ... you can then in a second connect to that (or another) site, use the
341 cookies from the 'headers' file like:
343 curl -b headers www.example.com
345 Note that by specifying -b you enable the "cookie awareness" and with -L
346 you can make curl follow a location: (which often is used in combination
347 with cookies). So that if a site sends cookies and a location, you can
348 use a non-existing file to trig the cookie awareness like:
350 curl -L -b empty-file www.example.com
352 The file to read cookies from must be formatted using plain HTTP headers OR
353 as netscape's cookie file. Curl will determine what kind it is based on the
358 The progress meter exists to show a user that something actually is
359 happening. The different fields in the output have the following meaning:
361 % Total % Received % Xferd Average Speed Time Curr.
362 Dload Upload Total Current Left Speed
363 0 151M 0 38608 0 0 9406 0 4:41:43 0:00:04 4:41:39 9287
366 % - percentage completed of the whole transfer
367 Total - total size of the whole expected transfer
368 % - percentage completed of the download
369 Received - currently downloaded amount of bytes
370 % - percentage completed of the upload
371 Xferd - currently uploaded amount of bytes
373 Dload - the average transfer speed of the download
375 Upload - the average transfer speed of the upload
376 Time Total - expected time to complete the operation
377 Time Current - time passed since the invoke
378 Time Left - expected time left to completetion
379 Curr.Speed - the average transfer speed the last 5 seconds (the first
380 5 seconds of a transfer is based on less time of course.)
382 The -# option will display a totally different progress bar that doesn't
383 need much explanation!
387 Curl offers the user to set conditions regarding transfer speed that must
388 be met to let the transfer keep going. By using the switch -y and -Y you
389 can make curl abort transfers if the transfer speed doesn't exceed your
390 given lowest limit for a specified time.
392 To let curl abandon downloading this page if its slower than 3000 bytes per
393 second for 1 minute, run:
395 curl -y 3000 -Y 60 www.far-away-site.com
397 This can very well be used in combination with the overall time limit, so
398 that the above operatioin must be completed in whole within 30 minutes:
400 curl -m 1800 -y 3000 -Y 60 www.far-away-site.com
404 Curl automatically tries to read the .curlrc file (or _curlrc file on win32
405 systems) from the user's home dir on startup.
407 The config file could be made up with normal command line switches, but you
408 can also specify the long options without the dashes to make it more
409 readable. You can separate the options and the parameter with spaces, or
410 with = or :. Comments can be used within the file. If the first letter on a
411 line is a '#'-letter the rest of the line is treated as a comment.
413 If you want the parameter to contain spaces, you must inclose the entire
414 parameter within double quotes ("). Within those quotes, you specify a
417 NOTE: You must specify options and their arguments on the same line.
419 Example, set default time out and proxy in a config file:
421 # We want a 30 minute timeout:
423 # ... and we use a proxy for all accesses:
424 proxy = proxy.our.domain.com:8080
426 White spaces ARE significant at the end of lines, but all white spaces
427 leading up to the first characters of each line are ignored.
429 Prevent curl from reading the default file by using -q as the first command
430 line parameter, like:
432 curl -q www.thatsite.com
434 Force curl to get and display a local help page in case it is invoked
435 without URL by making a config file similar to:
438 url = "http://help.with.curl.com/curlhelp.html"
440 You can specify another config file to be read by using the -K/--config
441 flag. If you set config file name to "-" it'll read the config from stdin,
442 which can be handy if you want to hide options from being visible in process
445 echo "user = user:passwd" | curl -K - http://that.secret.site.com
449 When using curl in your own very special programs, you may end up needing
450 to pass on your own custom headers when getting a web page. You can do
451 this by using the -H flag.
453 Example, send the header "X-you-and-me: yes" to the server when getting a
456 curl -H "X-you-and-me: yes" www.love.com
458 This can also be useful in case you want curl to send a different text in
459 a header than it normally does. The -H header you specify then replaces the
460 header curl would normally send.
464 Do note that when getting files with the ftp:// URL, the given path is
465 relative the directory you enter. To get the file 'README' from your home
466 directory at your ftp site, do:
468 curl ftp://user:passwd@my.site.com/README
470 But if you want the README file from the root directory of that very same
471 site, you need to specify the absolute file name:
473 curl ftp://user:passwd@my.site.com//README
475 (I.e with an extra slash in front of the file name.)
479 The FTP protocol requires one of the involved parties to open a second
480 connction as soon as data is about to get transfered. There are two ways to
483 The default way for curl is to issue the PASV command which causes the
484 server to open another port and await another connection performed by the
485 client. This is good if the client is behind a firewall that don't allow
486 incoming connections.
488 curl ftp.download.com
490 If the server for example, is behind a firewall that don't allow connections
491 on other ports than 21 (or if it just doesn't support the PASV command), the
492 other way to do it is to use the PORT command and instruct the server to
493 connect to the client on the given (as parameters to the PORT command) IP
496 The -P flag to curl supports a few different options. Your machine may have
497 several IP-addresses and/or network interfaces and curl allows you to select
498 which of them to use. Default address can also be used:
500 curl -P - ftp.download.com
502 Download with PORT but use the IP address of our 'le0' interface (this does
503 not work on windows):
505 curl -P le0 ftp.download.com
507 Download with PORT but use 192.168.0.10 as our IP address to use:
509 curl -P 192.168.0.10 ftp.download.com
513 Get a web page from a server using a specified port for the interface:
515 curl --interface eth0:1 http://www.netscape.com/
519 curl --interface 192.168.1.10 http://www.netscape.com/
523 Secure HTTP requires SSL libraries to be installed and used when curl is
524 built. If that is done, curl is capable of retrieving and posting documents
525 using the HTTPS procotol.
529 curl https://www.secure-site.com
531 Curl is also capable of using your personal certificates to get/post files
532 from sites that require valid certificates. The only drawback is that the
533 certificate needs to be in PEM-format. PEM is a standard and open format to
534 store certificates with, but it is not used by the most commonly used
535 browsers (Netscape and MSEI both use the so called PKCS#12 format). If you
536 want curl to use the certificates you use with your (favourite) browser, you
537 may need to download/compile a converter that can convert your browser's
538 formatted certificates to PEM formatted ones. This kind of converter is
539 included in recent versions of OpenSSL, and for older versions Dr Stephen
540 N. Henson has written a patch for SSLeay that adds this functionality. You
541 can get his patch (that requires an SSLeay installation) from his site at:
542 http://www.drh-consultancy.demon.co.uk/
544 Example on how to automatically retrieve a document using a certificate with
547 curl -E /path/to/cert.pem:password https://secure.site.com/
549 If you neglect to specify the password on the command line, you will be
550 prompted for the correct password before any data can be received.
552 Many older SSL-servers have problems with SSLv3 or TLS, that newer versions
553 of OpenSSL etc is using, therefore it is sometimes useful to specify what
554 SSL-version curl should use. Use -3 or -2 to specify that exact SSL version
557 curl -2 https://secure.site.com/
559 Otherwise, curl will first attempt to use v3 and then v2.
561 To use OpenSSL to convert your favourite browser's certificate into a PEM
562 formatted one that curl can use, do something like this (assuming netscape,
563 but IE is likely to work similarly):
565 You start with hitting the 'security' menu button in netscape.
567 Select 'certificates->yours' and then pick a certificate in the list
569 Press the 'export' button
571 enter your PIN code for the certs
573 select a proper place to save it
575 Run the 'openssl' application to convert the certificate. If you cd to the
576 openssl installation, you can do it like:
578 # ./apps/openssl pkcs12 -certfile [file you saved] -out [PEMfile]
581 RESUMING FILE TRANSFERS
583 To continue a file transfer where it was previously aborted, curl supports
584 resume on http(s) downloads as well as ftp uploads and downloads.
586 Continue downloading a document:
588 curl -c -o file ftp://ftp.server.com/path/file
590 Continue uploading a document(*1):
592 curl -c -T file ftp://ftp.server.com/path/file
594 Continue downloading a document from a web server(*2):
596 curl -c -o file http://www.server.com/
598 (*1) = This requires that the ftp server supports the non-standard command
599 SIZE. If it doesn't, curl will say so.
601 (*2) = This requires that the wb server supports at least HTTP/1.1. If it
602 doesn't, curl will say so.
606 HTTP allows a client to specify a time condition for the document it
607 requests. It is If-Modified-Since or If-Unmodified-Since. Curl allow you to
608 specify them with the -z/--time-cond flag.
610 For example, you can easily make a download that only gets performed if the
611 remote file is newer than a local copy. It would be made like:
613 curl -z local.html http://remote.server.com/remote.html
615 Or you can download a file only if the local file is newer than the remote
616 one. Do this by prepending the date string with a '-', as in:
618 curl -z -local.html http://remote.server.com/remote.html
620 You can specify a "free text" date as condition. Tell curl to only download
621 the file if it was updated since yesterday:
623 curl -z yesterday http://remote.server.com/remote.html
625 Curl will then accept a wide range of date formats. You always make the date
626 check the other way around by prepending it with a dash '-'.
632 curl dict://dict.org/m:curl
633 curl dict://dict.org/d:heisenbug:jargon
634 curl dict://dict.org/d:daniel:web1913
636 Aliases for 'm' are 'match' and 'find', and aliases for 'd' are 'define'
637 and 'lookup'. For example,
639 curl dict://dict.org/find:curl
641 Commands that break the URL description of the RFC (but not the DICT
644 curl dict://dict.org/show:db
645 curl dict://dict.org/show:strat
647 Authentication is still missing (but this is not required by the RFC)
651 If you have installed the OpenLDAP library, curl can take advantage of it
652 and offer ldap:// support.
654 LDAP is a complex thing and writing an LDAP query is not an easy task. I do
655 advice you to dig up the syntax description for that elsewhere, RFC 1959 if
656 no other place is better.
658 To show you an example, this is now I can get all people from my local LDAP
659 server that has a certain sub-domain in their email address:
661 curl -B "ldap://ldap.frontec.se/o=frontec??sub?mail=*sth.frontec.se"
663 If I want the same info in HTML format, I can get it by not using the -B
664 (enforce ASCII) flag.
666 ENVIRONMENT VARIABLES
668 Curl reads and understands the following environment variables:
670 HTTP_PROXY, HTTPS_PROXY, FTP_PROXY, GOPHER_PROXY
672 They should be set for protocol-specific proxies. General proxy should be
677 A comma-separated list of host names that shouldn't go through any proxy is
678 set in (only an asterisk, '*' matches all hosts)
682 If a tail substring of the domain-path for a host matches one of these
683 strings, transactions with that node will not be proxied.
686 The usage of the -x/--proxy flag overrides the environment variables.
690 Unix introduced the .netrc concept a long time ago. It is a way for a user
691 to specify name and password for commonly visited ftp sites in a file so
692 that you don't have to type them in each time you visit those sites. You
693 realize this is a big security risk if someone else gets hold of your
694 passwords, so therefor most unix programs won't read this file unless it is
695 only readable by yourself (curl doesn't care though).
697 Curl supports .netrc files if told so (using the -n/--netrc option). This is
698 not restricted to only ftp, but curl can use it for all protocols where
699 authentication is used.
701 A very simple .netrc file could look something like:
703 machine curl.haxx.se login iamdaniel password mysecret
707 To better allow script programmers to get to know about the progress of
708 curl, the -w/--write-out option was introduced. Using this, you can specify
709 what information from the previous transfer you want to extract.
711 To display the amount of bytes downloaded together with some text and an
714 curl -w 'We downloaded %{size_download} bytes\n' www.download.com
716 KERBEROS4 FTP TRANSFER
718 Curl supports kerberos4 for FTP transfers. You need the kerberos package
719 installed and used at curl build time for it to be used.
721 First, get the krb-ticket the normal way, like with the kauth tool. Then use
722 curl in way similar to:
724 curl --krb4 private ftp://krb4site.com -u username:fakepwd
726 There's no use for a password on the -u switch, but a blank one will make
727 curl ask for one and you already entered the real password to kauth.
731 We have an open mailing list to discuss curl, its development and things
734 To subscribe, mail curl-request@contactor.se with "subscribe <fill in your
735 email address>" in the body.
737 To post to the list, mail curl@contactor.se.
739 To unsubcribe, mail curl-request@contactor.se with "unsubscribe <your
740 subscribed email address>" in the body.