diff options
Diffstat (limited to 'README.curl')
| -rw-r--r-- | README.curl | 611 |
1 files changed, 611 insertions, 0 deletions
diff --git a/README.curl b/README.curl new file mode 100644 index 000000000..00f685e41 --- /dev/null +++ b/README.curl @@ -0,0 +1,611 @@ +LATEST VERSION + + You always find news about what's going on as well as the latest versions + from the curl web pages, located at: + + http://curl.haxx.nu + +SIMPLE USAGE + + Get the main page from netscape's web-server: + + curl http://www.netscape.com/ + + Get the root README file from funet's ftp-server: + + curl ftp://ftp.funet.fi/README + + Get a gopher document from funet's gopher server: + + curl gopher://gopher.funet.fi + + Get a web page from a server using port 8000: + + curl http://www.weirdserver.com:8000/ + + Get a list of the root directory of an FTP site: + + curl ftp://ftp.fts.frontec.se/ + + Get the definition of curl from a dictionary: + + curl dict://dict.org/m:curl + +DOWNLOAD TO A FILE + + 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.netscape.com/index.html + +USING PASSWORDS + + FTP + + To ftp files using name+passwd, include them in the URL like: + + curl ftp://name:passwd@machine.domain:port/full/path/to/file + + or specify them with the -u flag like + + curl -u name:passwd ftp://machine.domain:port/full/path/to/file + + HTTP + + The HTTP URL doesn't support user and password in the URL string. Curl + does support that anyway to provide a ftp-style interface and thus you can + pick a file like: + + curl http://name:passwd@machine.domain/full/path/to/file + + or specify user and password separately like in + + curl -u name:passwd http://machine.domain/full/path/to/file + + NOTE! Since HTTP URLs don't support user and password, you can't use that + style when using Curl via a proxy. You _must_ use the -u style fetch + during such circumstances. + + HTTPS + + Probably most commonly used with private certificates, as explained below. + + GOPHER + + Curl features no password support for gopher. + +PROXY + + 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/ + + See also the environment variables Curl support that offer further proxy + control. + +RANGES + + 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 flag. + + 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 + +UPLOADING + + FTP + + Upload all data on stdin to a specified ftp site: + + curl -t ftp://ftp.upload.com/myfile + + Upload data from a specified file, login with user and password: + + curl -T uploadfile -u user:passwd ftp://ftp.upload.com/myfile + + Upload a local file to the remote site, and use the local file name remote + too: + + curl -T uploadfile -u user:passwd ftp://ftp.upload.com/ + + NOTE: Curl is not currently supporing ftp upload through a proxy! The reason + for this is simply that proxies are seldomly configured to allow this and + that no author has supplied code that makes it possible! + + HTTP + + Upload all data on stdin to a specified http site: + + curl -t http://www.upload.com/myfile + + Note that the http server must've been configured to accept PUT before this + can be done successfully. + + For other ways to do http data upload, see the POST section below. + +VERBOSE / DEBUG + + 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 -v flag to get VERBOSE + fetching. Curl will output lots of info and all data it sends and + receives in order to let the user see all client-server interaction. + + curl -v ftp://ftp.upload.com/ + +DETAILED INFORMATION + + 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: + + curl --dump-header headers.txt curl.haxx.nu + + 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. + +POST (HTTP) + + It's easy to post data using curl. This is done using the -d <data> + option. The post data must be urlencoded. + + Post a simple "name" and "phone" guestbook. + + curl -d "name=Rafael%20Sagula&phone=3320780" \ + http://www.where.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. + + -F accepts parameters like -F "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 which content type the file is, by appending + ';type=<mime type>' to the file name. You can also post contents of several + files in one field. So that the field name 'coolfiles' can be sent three + files with different content types in a manner similar to: + + curl -F "coolfiles=@fil1.gif;type=image/gif,fil2.txt,fil3.html" \ + http://www.post.com/postit.cgi + + If content-type is not specified, curl will try to guess from the 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 finally 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 check out the HTML of the form page to get to + know 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 + + So, 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" + +REFERER + + A HTTP request has the option to include information about which address + that referred to actual page, and curl allows the user to specify that + referrer to get specified 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/ + +USER AGENT + + 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/3.0 (Win95; I)' Netscape Version 3 for Windows 95 + 'Mozilla/3.04 (Win95; U)' Netscape Version 3 for Windows 95 + 'Mozilla/2.02 (OS/2; U)' Netscape Version 2 for OS/2 + 'Mozilla/4.04 [en] (X11; U; AIX 4.2; Nav)' NS for AIX + '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 + +COOKIES + + Cookies are generally used by web servers to keep state information at the + client's side. The server sets cookies by sending a response line in the + headers that looks like 'Set-Cookie: <data>' where the data part then + typically contains a set of NAME=VALUE pairs (separated by semicolons ';' + like "NAME1=VALUE1; NAME2=VALUE2;"). The server can also specify for what + path the "cookie" should be used for (by specifying "path=value"), when the + cookie should expire ("expire=DATE"), for what domain to use it + ("domain=NAME") and if it should be used on secure connections only + ("secure"). + + If you've received a page from a server that contains a header like: + Set-Cookie: sessionid=boo123; path="/foo"; + + it 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.sillypage.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 + + Note that by specifying -b you enable the "cookie awareness" and with -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 trig the cookie awareness like: + + curl -L -b empty-file 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. + +PROGRESS METER + + The progress meter was introduced to better show a user that something + actually is happening. The different fields in the output have the following + meaning: + + % Received Total Speed Time left Total Curr.Speed + 13 524140 3841536 4296 0:12:52 0:14:54 292 + + From left-to-right: + - The first column, is the percentage of the file currently transfered. + - Received means the total number of bytes that has been transfered. + - Total is the total number of bytes expected to transfer. + - Speed is average speed in bytes per second for the whole transfer so far. + - Time left is the estimated time left for this transfer to finnish if the + current average speed will remain steady. + - Total is the estimated total transfer time. + - Curr.Speed is the average transfer speed the last 5 seconds (the first + 5 seconds of a transfer is based on less time of course.) + + NOTE: Much of the output is based on the fact that the size of the transfer + is known before it takes place. If it isn't, a much less fancy display will + be used. + +SPEED LIMIT + + Curl offers the user to set conditions regarding transfer speed that must + be met to let the transfer keep going. By using the switch -y and -Y you + can make curl abort transfers if the transfer speed doesn't exceed your + given lowest limit for a specified time. + + To let curl abandon downloading this page if its 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 operatioin must be completed in whole within 30 minutes: + + curl -m 1800 -y 3000 -Y 60 www.far-away-site.com + +CONFIG FILE + + 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 should be + made up with normal command line switches. 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. + + Example, set default time out and proxy in a config file: + + # We want a 30 minute timeout: + -m 1800 + # ... and we use a proxy for all accesses: + -x 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 + http://help.with.curl.com/curlhelp.html + + You can specify another config file to be read by using the -K/--config + flag. 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 "-u user:passwd" | curl -K - http://that.secret.site.com + +EXTRA HEADERS + + 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 flag. + + 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. + +FTP and PATH NAMES + + 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.) + +FTP and firewalls + + 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. + + The -P flag to curl allows for 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: + + 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 + +HTTPS + + Secure HTTP requires SSLeay to be installed and used when curl is built. If + that is done, curl is capable of retrieving and posting documents using the + HTTPS procotol. + + Example: + + curl https://www.secure-site.com + + Curl is also capable of using your personal certificates to get/post files + from sites that require valid certificates. The only drawback is that the + certificate needs to be in PEM-format. PEM is a standard and open format to + store certificates with, but it is not used by the most commonly used + browsers (Netscape and MSEI both use the so called PKCS#12 format). If you + want curl to use the certificates you use with your (favourite) browser, you + may need to download/compile a converter that can convert your browser's + formatted certificates to PEM formatted ones. Dr Stephen N. Henson has + written a patch for SSLeay that adds this functionality. You can get his + patch (that requires an SSLeay installation) from his site at: + http://www.drh-consultancy.demon.co.uk/ + + Example on how to automatically retrieve a document using a certificate with + a personal password: + + curl -E /path/to/cert.pem:password https://secure.site.com/ + + If you neglect to specify the password on the command line, you will be + prompted for the correct password before any data can be received. + + Many older SSL-servers have problems with SSLv3 or TLS, that newer versions + of OpenSSL etc is using, therefore it is sometimes useful to specify what + SSL-version curl should use. Use -3 or -2 to specify that exact SSL version + to use: + + curl -2 https://secure.site.com/ + + Otherwise, curl will first attempt to use v3 and then v2. + +RESUMING FILE TRANSFERS + + 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 wb server supports at least HTTP/1.1. If it + doesn't, curl will say so. + +TIME CONDITIONS + + 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 flag. + + 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 '-'. + +DICT + + For fun try + + curl dict://dict.org/m:curl + curl dict://dict.org/d:heisenbug:jargon + curl dict://dict.org/d:daniel:web1913 + + Aliases for 'm' are 'match' and 'find', and aliases for 'd' are 'define' + and 'lookup'. For example, + + curl dict://dict.org/find:curl + + Commands that break the URL description of the RFC (but not the DICT + protocol) are + + curl dict://dict.org/show:db + curl dict://dict.org/show:strat + + Authentication is still missing (but this is not required by the RFC) + +LDAP + + 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, RFC 1959 if + no other place is better. + + 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) flag. + +ENVIRONMENT VARIABLES + + Curl reads and understands the following environment variables: + + HTTP_PROXY, HTTPS_PROXY, FTP_PROXY, GOPHER_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 flag overrides the environment variables. + +MAILING LIST + + We have an open mailing list to discuss curl, its development and things + relevant to this. + + To subscribe, mail curl-request@contactor.se with "subscribe <your email + address>" in the body. + + To post to the list, mail curl@contactor.se. + + To unsubcribe, mail curl-request@contactor.se with "unsubscribe <your + subscribed email address>" in the body. + |