program - Description
program [options]
Print available options.
Print the version number.
For more complete documentation refer to http://curl.haxx.se/docs/manual.html
Get the main page:
curl http://www.google.com/
Get a directory listing with port number:
curl ftp://www.haxx.se:2121/
Fetch two documents at once:
curl ftp://www.haxx.se/ http://www.weirdserver.com:8000/
Get the definition of curl from a dictionary:
curl dict://dict.org/m:curl
Get a file off an FTPS server:
curl ftps://files.are.secure.com/secrets.txt
A better way to get file from FTPS:
curl --ftp-ssl ftp://files.are.secure.com/secrets.txt
Some sites do not allow robots, so pretend to be a browser by changing User-Agent:. In addition pretent the requets to come from another source by changing Refferer:
curl -A 'Mozilla/5.0' -e www.cool.com ftp://www.haxx.se/
To see if the page is there, retrieve only first 100 bytes:
curl -r 0-99 http://www.example.com/
Basic use:
curl ftp://name:passwd@machine.domain:port/full/path/to/file
curl http://name:passwd@machine.domain:port/full/path/to/file
And through proxy:
http_proxy=http://proxy:port
curl http://name:passwd@machine.domain:port/full/path/to/file
Some proxies require special authentication. Here is example pecifying proxy with -x option
curl -U user:passwd -x my-proxy:888 http://www.get.this/
The FTPS is just like FTP, but you may also want to specify and use SSL-specific options for certificates etc. Note that using ftps:// as prefix is the "implicit" way as described in the standards while the recommended "explicit" way is done by using ftp:// and the --ftp-ssl option.
Note, that HTTP offers many different methods of authentication and curl supports several: Basic, Digest, NTLM and Negotiate. Without telling which method to use, curl defaults to Basic. You can also ask curl to pick the most secure ones out of the ones that the server accepts for the given URL, by using option --anyauth.
When using Curl via a proxy, you may need to use -u if you need to send passwords.
Get a web page and store in a local file:
curl -o thatpage.html http://www.netscape.com/
Get a web page and store in a local file, make the local file get the name of the remote document (if no file name part is specified in the URL, this will fail):
curl -O http://www.google.com/index.html
Fetch two files and store them with their remote names:
curl -O www.haxx.se/index.html -O curl.haxx.se/download.html
To continue a file transfer where it was previously aborted, curl supports resume on http(s) downloads as well as ftp uploads and downloads.
Continue downloading a document:
curl -C - -o file ftp://ftp.server.com/path/file
Continue uploading a document(*1):
curl -C - -T file ftp://ftp.server.com/path/file
Continue downloading a document from a web server(*2):
curl -C - -o file http://www.server.com/
(*1) = This requires that the ftp server supports the non-standard command SIZE. If it doesn't, curl will say so.
(*2) = This requires that the web server supports at least HTTP/1.1. If it doesn't, curl will say so.
HTTP allows a client to specify a time condition for the document it requests. It is If-Modified-Since or If-Unmodified-Since. Curl allow you to specify them with the -z/--time-cond option.
For example, you can easily make a download that only gets performed if the remote file is newer than a local copy. It would be made like:
curl -z local.html http://remote.server.com/remote.html
Or you can download a file only if the local file is newer than the remote one. Do this by prepending the date string with a '-', as in:
curl -z -local.html http://remote.server.com/remote.html
You can specify a "free text" date as condition. Tell curl to only download the file if it was updated since yesterday:
curl -z yesterday http://remote.server.com/remote.html
Curl will then accept a wide range of date formats. You always make the date check the other way around by prepending it with a dash '-'.
Get an ftp file using a proxy named my-proxy that uses port 888:
curl -x my-proxy:888 ftp://ftp.leachsite.com/README
Get a file from a HTTP server that requires user and password, using the same proxy as above:
curl -u user:passwd -x my-proxy:888 http://www.get.this/
Some proxies require special authentication. Specify by using -U as above:
curl -U user:passwd -x my-proxy:888 http://www.get.this/
Curl also supports SOCKS4 and SOCKS5 proxies with --socks4 and --socks5. See also the environment variables Curl support that offer further proxy control.
With HTTP 1.1 byte-ranges were introduced. Using this, a client can request to get only one or more subparts of a specified document. Curl supports this with the -r option.
Get the first 100 bytes of a document:
curl -r 0-99 http://www.get.this/
Get the last 500 bytes of a document:
curl -r -500 http://www.get.this/
Curl also supports simple ranges for FTP files as well. Then you can only specify start and stop position.
Get the first 100 bytes of a document using FTP:
curl -r 0-99 ftp://www.get.this/README
Upload all data on stdin to a specified ftp site:
curl -T - ftp://ftp.example.com/myfile
Upload file.txt with login and password:
curl -T file.txt ftp://login:pass@ftp.example.com/myfile
Upload a local file to get appended to the remote file using ftp:
curl -T localfile -a ftp://ftp.upload.com/remotefile
Upload using HTTP PUT:
curl -T file.txt http://www.example.com/
In case the upload must go through HTTP proxy, add option --proxytunnel. This only works for HTTP proxys. Curl does not support pure FTP proxys.
curl -p -x proxy:port -T file.txt ftp.exmaple.com
It's easy to post data using curl. This is done using the -d option. Post a simple "name" and "phone" fields to guestbook. The post data must have been urlencoded by you:
curl -d "name=foo&phone=3320780" http://www.example.com/guest.cgi
While -d uses the application/x-www-form-urlencoded mime-type, generally understood by CGI's and similar, curl also supports the more capable multipart/form-data type. This latter type supports things like file upload.
Option -F accepts parameters in format "name=contents". If you want the contents to be read from a file, use @filename as contents. When specifying a file, you can also specify the file content type by appending ';type=<mime type>' to the file name. You can also post the contents of several files in one field. For example, the field name 'coolfiles' is used to send three files, with different content types using the following syntax:
curl -F "coolfiles=@fil1.gif;type=image/gif,fil2.txt,fil3.html" \
http://www.post.com/postit.cgi
If the content-type is not specified, curl will try to guess from the file extension (it only knows a few), or use the previously specified type (from an earlier file if several files are specified in a list) or else it will using the default type 'text/plain'.
Emulate a fill-in form with -F. Let's say you fill in three fields in a form. One field is a file name which to post, one field is your name and one field is a file description. We want to post the file we have written named "cooltext.txt". To let curl do the posting of this data instead of your favourite browser, you have to read the HTML source of the form page and find the names of the input fields. In our example, the input field names are 'file', 'yourname' and 'filedescription'.
curl -F "file=@cooltext.txt" \
-F "yourname=Daniel" \
-F "filedescription=Cool text file with cool text inside" \
http://www.post.com/postit.cgi
Suppose the HTML form is in site that requires registration information before download link appears. In that case, add option -L/--location to make curl follow the announced 'Location:' header in the HTTP response. If it's a binary file, then you need to redirect the output to file.
curl -F "first_name=Foo" \
-F "last_name=Bar" \
-L \
-o package.tar.gz \
http://www.example.com/postit.cgi
To send two files in one post you can do it in two ways:
1. Send multiple files in a single "field" with a single field name:
curl -F "pictures=@dog.gif,cat.gif"
2. Send two fields with two field names: curl -F "docpicture=@dog.gif" -F "catpicture=@cat.gif"
To send a field value literally without interpreting a leading '@' or '<', or an embedded ';type=', use --form-string instead of -F. This is recommended when the value is obtained from a user or some other unpredictable source. Under these circumstances, using -F instead of --form-string would allow a user to trick curl into uploading a file.
Dig out all the <input> tags in the form that you want to fill in. (There's a perl program called formfind.pl on the curl site that helps with this). If there's a "normal" post, you use -d to post. This option takes a full "post string", which is in the format
<variable1>=<data1>&<variable2>=<data2>&...
The 'variable' names are the names set with "name=" in the <input> tags, and the data is the contents you want to fill in for the inputs. The data *must* be properly URL encoded. That means you replace space with + and that you write weird letters with %XX where XX is the hexadecimal representation of the letter's ASCII code. An Example from http://www.formpost.com/getthis/
<form action="post.cgi" method="post">
<input name=user size=10>
<input name=pass type=password size=10>
<input name=id type=hidden value="blablabla">
<input name=ding value="submit">
</form>
A HTTP request has the option to include information about which address that referred to actual page. Curl allows you to specify the referrer to be used on the command line. It is especially useful to fool or trick stupid servers or CGI scripts that rely on that information being available or contain certain data.
curl -e www.coolsite.com http://www.showme.com/
NOTE: The referer field is defined in the HTTP spec to be a full URL.
A HTTP request has the option to include information about the browser that generated the request. Curl allows it to be specified on the command line. It is especially useful to fool or trick stupid servers or CGI scripts that only accept certain browsers.
Example:
curl -A 'Mozilla/3.0 (Win95; I)' http://www.nationsbank.com/
Other common strings:
'Mozilla/4.05 [en] (X11; U; Linux 2.0.32 i586)' NS for Linux
Note that Internet Explorer tries hard to be compatible in every way:
'Mozilla/4.0 (compatible; MSIE 4.01; Windows 95)' MSIE for W95
Mozilla is not the only possible User-Agent name:
'Konqueror/1.0' KDE File Manager desktop client
'Lynx/2.7.1 libwww-FM/2.14' Lynx command line browser
The cookie response header looks like this:
Set-Cookie: sessionid=boo123; path="/foo";
This means the server wants that first pair passed on when we get anything in a path beginning with "/foo".
Example, get a page that wants my name passed in a cookie:
curl -b "name=Daniel" www.example.com
Curl also has the ability to use previously received cookies in following sessions. If you get cookies from a server and store them in a file in a manner similar to:
curl --dump-header headers www.example.com
... you can then in a second connect to that (or another) site, use the cookies from the 'headers' file like:
curl -b headers www.example.com
While saving headers to a file is a working way to store cookies, it is however error-prone and not the preferred way to do this. Instead, make curl save the incoming cookies using the well known cookie format like this:
curl -c cookies.txt www.example.com
Note that by specifying -b you enable the "cookie awareness" and with option -L you can make curl follow a location: (which often is used in combination with cookies). So that if a site sends cookies and a location, you can use a non-existing file to trigger the cookie awareness like:
curl -L -b empty.txt www.example.com
The file to read cookies from must be formatted using plain HTTP headers OR as netscape's cookie file. Curl will determine what kind it is based on the file contents. In the above command, curl will parse the header and store the cookies received from www.example.com. curl will send to the server the stored cookies which match the request as it follows the location. The file "empty.txt" may be a nonexistent file.
Alas, to both read and write cookies from a netscape cookie file, you can set both -b and -c to use the same file:
curl -b cookies.txt -c cookies.txt www.example.com
The progress meter exists to show a user that something actually is happening. The different fields in the output have the following meaning:
% Total % Received % Xferd Average Speed Time Curr.
Dload Upload Total Current Left Speed
0 151M 0 38608 0 0 9406 0 4:41:43 0:00:04 4:41:39 9287
From left-to-right:
% - percentage completed of the whole transfer
Total - total size of the whole expected transfer
% - percentage completed of the download
Received - currently downloaded amount of bytes
% - percentage completed of the upload
Xferd - currently uploaded amount of bytes
Average Speed
Dload - the average transfer speed of the download
Average Speed
Upload - the average transfer speed of the upload
Time Total - expected time to complete the operation
Time Current - time passed since the invoke
Time Left - expected time left to completion
Curr.Speed - the average transfer speed the last 5 seconds (the first
5 seconds of a transfer is based on less time of course.)
Curl allows the user to set the transfer speed conditions that must be met to let the transfer keep going. By using the option -y and -Y you can make curl abort transfers if the transfer speed is below the specified lowest limit for a specified time.
To have curl abort the download if the speed is slower than 3000 bytes per second for 1 minute, run:
curl -Y 3000 -y 60 www.far-away-site.com
This can very well be used in combination with the overall time limit, so that the above operation must be completed in whole within 30 minutes:
curl -m 1800 -Y 3000 -y 60 www.far-away-site.com
Forcing curl not to transfer data faster than a given rate is also possible, which might be useful if you're using a limited bandwidth connection and you don't want your transfer to use all of it (sometimes referred to as "bandwidth throttle").
Make curl transfer data no faster than 10 kilobytes per second:
curl --limit-rate 10K www.far-away-site.com
or
curl --limit-rate 10240 www.far-away-site.com
Or prevent curl from uploading data faster than 1 megabyte per second:
curl -T upload --limit-rate 1M ftp://uploadshereplease.com
When using the --limit-rate option, the transfer rate is regulated on a per-second basis, which will cause the total transfer speed to become lower than the given number. Sometimes of course substantially lower, if your transfer stalls during periods.
Curl automatically tries to read the .curlrc file (or _curlrc file on win32 systems) from the user's home dir on startup.
The config file could be made up with normal command line optionss, but you can also specify the long options without the dashes to make it more readable. You can separate the options and the parameter with spaces, or with = or :. Comments can be used within the file. If the first letter on a line is a '#'-letter the rest of the line is treated as a comment.
If you want the parameter to contain spaces, you must inclose the entire parameter within double quotes ("). Within those quotes, you specify a quote as \".
NOTE: You must specify options and their arguments on the same line.
Example, set default time out and proxy in a config file:
# Set 30 minute timeout -m 1800
# and we use a proxy for all accesses:
proxy = proxy.our.domain.com:8080
White spaces ARE significant at the end of lines, but all white spaces leading up to the first characters of each line are ignored.
Prevent curl from reading the default file by using -q as the first command line parameter, like:
curl -q www.thatsite.com
Force curl to get and display a local help page in case it is invoked without URL by making a config file similar to:
# default url to get
url = "http://help.with.curl.com/curlhelp.html"
You can specify another config file to be read by using the -K/--config option. If you set config file name to "-" it'll read the config from stdin, which can be handy if you want to hide options from being visible in process tables etc:
echo "user = user:passwd" | curl -K - http://that.secret.site.com
When using curl in your own very special programs, you may end up needing to pass on your own custom headers when getting a web page. You can do this by using the -H option.
Example, send the header "X-you-and-me: yes" to the server when getting a page:
curl -H "X-you-and-me: yes" www.love.com
This can also be useful in case you want curl to send a different text in a header than it normally does. The -H header you specify then replaces the header curl would normally send. If you replace an internal header with an empty one, you prevent that header from being sent. To prevent the Host: header from being used:
curl -H "Host:" www.server.com
Do note that when getting files with the ftp:// URL, the given path is relative the directory you enter. To get the file 'README' from your home directory at your ftp site, do:
curl ftp://user:passwd@my.site.com/README
But if you want the README file from the root directory of that very same site, you need to specify the absolute file name:
curl ftp://user:passwd@my.site.com//README
(I.e with an extra slash in front of the file name.)
The FTP protocol requires one of the involved parties to open a second connction as soon as data is about to get transfered. There are two ways to do this.
The default way for curl is to issue the PASV command which causes the server to open another port and await another connection performed by the client. This is good if the client is behind a firewall that don't allow incoming connections.
curl ftp.download.com
If the server for example, is behind a firewall that don't allow connections on other ports than 21 (or if it just doesn't support the PASV command), the other way to do it is to use the PORT command and instruct the server to connect to the client on the given (as parameters to the PORT command) IP number and port.
Use -P option make curl support few different options. Your machine may have several IP-addresses and/or network interfaces and curl allows you to select which of them to use. Default address can also be used:
curl -P - ftp.download.com
Download with PORT but use the IP address of our 'le0' interface (this does not work on windows):
curl -P le0 ftp.download.com
Download with PORT but use 192.168.0.10 as our IP address to use:
curl -P 192.168.0.10 ftp.download.com
Get a web page from a server using a specified port for the interface:
curl --interface eth0:1 http://www.netscape.com/
or
curl --interface 192.168.1.10 http://www.netscape.com/
If you have installed the OpenLDAP library, curl can take advantage of it and offer ldap:// support. LDAP is a complex thing and writing an LDAP query is not an easy task. I do advice you to dig up the syntax description for that elsewhere. Two places that might suit you are:
"Netscape Directory SDK 3.0 for C Programmer's Guide Chapter 10: Working with LDAP URLs" http://developer.netscape.com/docs/manuals/dirsdk/csdk30/url.htm
RFC 2255, "The LDAP URL Format" http://www.ietf.org/rfc/rfc2255.txt
To show you an example, this is now I can get all people from my local LDAP server that has a certain sub-domain in their email address:
curl -B "ldap://ldap.frontec.se/o=frontec??sub?mail=*sth.frontec.se"
If I want the same info in HTML format, I can get it by not using the -B (enforce ASCII) option.
Curl reads and understands the following environment variables:
http_proxy, HTTPS_PROXY, FTP_PROXY
They should be set for protocol-specific proxies. General proxy should be set with
ALL_PROXY
A comma-separated list of host names that shouldn't go through any proxy is set in (only an asterisk, '*' matches all hosts)
NO_PROXY
If a tail substring of the domain-path for a host matches one of these strings, transactions with that node will not be proxied.
The usage of the -x/--proxy option overrides the environment variables.
Curl reads and understands the following environment variables:
http_proxy, HTTPS_PROXY, FTP_PROXY
They should be set for protocol-specific proxies. General proxy should be set with
ALL_PROXY
A comma-separated list of host names that shouldn't go through any proxy is set in (only an asterisk, '*' matches all hosts)
NO_PROXY
If a tail substring of the domain-path for a host matches one of these strings, transactions with that node will not be proxied.
The usage of the -x/--proxy option overrides the environment variables.
Unix introduced the .netrc concept a long time ago. It is a way for a user to specify name and password for commonly visited ftp sites in a file so that you don't have to type them in each time you visit those sites. You realize this is a big security risk if someone else gets hold of your passwords, so therefore most unix programs won't read this file unless it is only readable by yourself (curl doesn't care though).
Curl supports .netrc files if told so (using the -n/--netrc and --netrc-optional options). This is not restricted to only ftp, but curl can use it for all protocols where authentication is used.
A very simple .netrc file could look something like:
machine curl.haxx.se login iamdaniel password mysecret
To better allow script programmers to get to know about the progress of curl, the -w/--write-out option was introduced. Using this, you can specify what information from the previous transfer you want to extract.
To display the amount of bytes downloaded together with some text and an ending newline:
curl -w 'We downloaded %{size_download} bytes\n' www.download.com
Curl supports kerberos4 for FTP transfers. You need the kerberos package installed and used at curl build time for it to be used.
First, get the krb-ticket the normal way, like with the kauth tool. Then use curl in way similar to:
curl --krb4 private ftp://krb4site.com -u username:fakepwd
There's no use for a password on the -u option, but a blank one will make curl ask for one and you already entered the real password to kauth.
The curl telnet support is basic and very easy to use. Curl passes all data passed to it on stdin to the remote server. Connect to a remote telnet server using a command line similar to:
curl telnet://remote.server.com
And enter the data to pass to the server on stdin. The result will be sent to stdout or to the file you specify with -o option.
You might want the -N/--no-buffer option to switch off the buffered output for slow connections or similar.
Pass options to the telnet protocol negotiation, by using the -t option. To tell the server we use a vt100 terminal, try something like:
curl -tTTYPE=vt100 telnet://remote.server.com
Other interesting options for it -t include:
- XDISPLOC=<X display> Sets the X display location.
- NEW_ENV=<var,val> Sets an environment variable.
NOTE: the telnet protocol does not specify any way to login with a specified user and password so curl can't do that automatically. To do that, you need to track when the login prompt is received and send the username and password accordingly.
Specifying multiple files on a single command line will make curl transfer all of them, one after the other in the specified order.
libcurl will attempt to use persistent connections for the transfers so that the second transfer to the same host can use the same connection that was already initiated and was left open in the previous transfer. This greatly decreases connection time for all but the first transfer and it makes a far better use of the network.
Note that curl cannot use persistent connections for transfers that are used in subsequence curl invokes. Try to stuff as many URLs as possible on the same command line if they are using the same host, as that'll make the transfers faster. If you use a http proxy for file transfers, practically all transfers will be persistent.
As is mentioned above, you can download multiple files with one command line by simply adding more URLs. If you want those to get saved to a local file instead of just printed to stdout, you need to add one save option for each URL you specify. Note that this also goes for the -O option.
For example: get two files and use -O for the first and a custom file name for the second:
curl -O http://url.com/file.txt ftp://ftp.com/moo.exe -o moo.jpg
You can also upload multiple files in a similar fashion:
curl -T local1 ftp://ftp.com/moo.exe -T local2 ftp://ftp.com/moo2.txt
Different protocols provide different ways of getting detailed information about specific files/documents. To get curl to show detailed information use option -I/--head option.
If curl fails where it isn't supposed to, if the servers don't let you in, if you can't understand the responses: use the option -v to get verbose fetching. Curl will output lots of info and what it sends and receives in order to let the user see all client-server interaction (but it won't show you the actual data).
curl -v ftp://ftp.upload.com/
To get even more details and information on what curl does, try using the --trace or --trace-ascii options with a given file name to log to, like this:
curl --trace trace.txt www.haxx.se
Different protocols provide different ways of getting detailed information about specific files/documents. To get curl to show detailed information about a single file, you should use -I/--head option. It displays all available info on a single file for HTTP and FTP. The HTTP information is a lot more extensive.
For HTTP, you can get the header information (the same as -I would show) shown before the data by using -i/--include. Curl understands the -D/--dump-header option when getting files from both FTP and HTTP, and it will then store the headers in the specified file.
Store the HTTP headers in a separate file (headers.txt in the example):
curl --dump-header headers.txt curl.haxx.se
Note that headers stored in a separate file can be very useful at a later time if you want curl to use cookies sent by the server. More about that in the cookies section.
None.
curl(1)