hugehelp.c

"  favourite browser, you have to check out the HTML of the form page to get to\n"
"  know the names of the input fields. In our example, the input field names are\n"
"  'file', 'yourname' and 'filedescription'.\n"
"\n"
"        curl -F \"file=@cooltext.txt\" -F \"yourname=Daniel\" \\\n"
"             -F \"filedescription=Cool text file with cool text inside\" \\\n"
"             http://www.post.com/postit.cgi\n"
"\n"
"  So, to send two files in one post you can do it in two ways:\n"
"\n"
"  1. Send multiple files in a single \"field\" with a single field name:\n"
" \n"
"        curl -F \"pictures=@dog.gif,cat.gif\" \n"
" \n"
"  2. Send two fields with two field names: \n"
"\n"
"        curl -F \"docpicture=@dog.gif\" -F \"catpicture=@cat.gif\" \n"
"\n"
"REFERER\n"
"\n"
"  A HTTP request has the option to include information about which address\n"
"  that referred to actual page, and curl allows the user to specify that\n"
"  referrer to get specified on the command line. It is especially useful to\n"
"  fool or trick stupid servers or CGI scripts that rely on that information\n"
"  being available or contain certain data.\n"
"\n"
"        curl -e www.coolsite.com http://www.showme.com/\n"
"\n"
"USER AGENT\n"
"\n"
"  A HTTP request has the option to include information about the browser\n"
"  that generated the request. Curl allows it to be specified on the command\n"
"  line. It is especially useful to fool or trick stupid servers or CGI\n"
"  scripts that only accept certain browsers.\n"
"\n"
"  Example:\n"
"\n"
"  curl -A 'Mozilla/3.0 (Win95; I)' http://www.nationsbank.com/\n"
"\n"
"  Other common strings:\n"
"    'Mozilla/3.0 (Win95; I)'     Netscape Version 3 for Windows 95\n"
"    'Mozilla/3.04 (Win95; U)'    Netscape Version 3 for Windows 95\n"
"    'Mozilla/2.02 (OS/2; U)'     Netscape Version 2 for OS/2\n"
"    'Mozilla/4.04 [en] (X11; U; AIX 4.2; Nav)'           NS for AIX\n"
"    'Mozilla/4.05 [en] (X11; U; Linux 2.0.32 i586)'      NS for Linux\n"
"\n"
"  Note that Internet Explorer tries hard to be compatible in every way:\n"
"    'Mozilla/4.0 (compatible; MSIE 4.01; Windows 95)'    MSIE for W95\n"
"\n"
"  Mozilla is not the only possible User-Agent name:\n"
"    'Konqueror/1.0'             KDE File Manager desktop client\n"
"    'Lynx/2.7.1 libwww-FM/2.14' Lynx command line browser\n"
"\n"
"COOKIES\n"
"\n"
"  Cookies are generally used by web servers to keep state information at the\n"
"  client's side. The server sets cookies by sending a response line in the\n"
"  headers that looks like 'Set-Cookie: <data>' where the data part then\n"
"  typically contains a set of NAME=VALUE pairs (separated by semicolons ';'\n"
"  like \"NAME1=VALUE1; NAME2=VALUE2;\"). The server can also specify for what\n"
);
 puts(
"  path the \"cookie\" should be used for (by specifying \"path=value\"), when the\n"
"  cookie should expire (\"expire=DATE\"), for what domain to use it\n"
"  (\"domain=NAME\") and if it should be used on secure connections only\n"
"  (\"secure\").\n"
"\n"
"  If you've received a page from a server that contains a header like:\n"
"        Set-Cookie: sessionid=boo123; path=\"/foo\";\n"
"\n"
"  it means the server wants that first pair passed on when we get anything in\n"
"  a path beginning with \"/foo\".\n"
"\n"
"  Example, get a page that wants my name passed in a cookie:\n"
"\n"
"        curl -b \"name=Daniel\" www.sillypage.com\n"
"\n"
"  Curl also has the ability to use previously received cookies in following\n"
"  sessions. If you get cookies from a server and store them in a file in a\n"
"  manner similar to:\n"
"\n"
"        curl --dump-header headers www.example.com\n"
"\n"
"  ... you can then in a second connect to that (or another) site, use the\n"
"  cookies from the 'headers' file like:\n"
"\n"
"        curl -b headers www.example.com\n"
"\n"
"  Note that by specifying -b you enable the \"cookie awareness\" and with -L\n"
"  you can make curl follow a location: (which often is used in combination\n"
"  with cookies). So that if a site sends cookies and a location, you can\n"
"  use a non-existing file to trig the cookie awareness like:\n"
"\n"
"        curl -L -b empty-file www.example.com\n"
"\n"
"  The file to read cookies from must be formatted using plain HTTP headers OR\n"
"  as netscape's cookie file. Curl will determine what kind it is based on the\n"
"  file contents.\n"
"\n"
"PROGRESS METER\n"
"\n"
"  The progress meter exists to show a user that something actually is\n"
"  happening. The different fields in the output have the following meaning:\n"
"\n"
"  % Total    % Received % Xferd  Average Speed          Time             Curr.\n"
"                                 Dload  Upload Total    Current  Left    Speed\n"
"  0  151M    0 38608    0     0   9406      0  4:41:43  0:00:04  4:41:39  9287\n"
"\n"
"  From left-to-right:\n"
"   %             - percentage completed of the whole transfer\n"
"   Total         - total size of the whole expected transfer\n"
"   %             - percentage completed of the download\n"
"   Received      - currently downloaded amount of bytes\n"
"   %             - percentage completed of the upload\n"
"   Xferd         - currently uploaded amount of bytes\n"
"   Average Speed\n"
"   Dload         - the average transfer speed of the download\n"
"   Average Speed\n"
"   Upload        - the average transfer speed of the upload\n"
"   Time Total    - expected time to complete the operation\n"
"   Time Current  - time passed since the invoke\n"
"   Time Left     - expected time left to completetion\n"
"   Curr.Speed    - the average transfer speed the last 5 seconds (the first\n"
"                   5 seconds of a transfer is based on less time of course.)\n"
"\n"
"  The -# option will display a totally different progress bar that doesn't\n"
"  need much explanation!\n"
"\n"
"SPEED LIMIT\n"
"\n"
"  Curl offers the user to set conditions regarding transfer speed that must\n"
"  be met to let the transfer keep going. By using the switch -y and -Y you\n"
"  can make curl abort transfers if the transfer speed doesn't exceed your\n"
"  given lowest limit for a specified time.\n"
"\n"
"  To let curl abandon downloading this page if its slower than 3000 bytes per\n"
"  second for 1 minute, run:\n"
"\n"
"        curl -y 3000 -Y 60 www.far-away-site.com\n"
"\n"
"  This can very well be used in combination with the overall time limit, so\n"
"  that the above operatioin must be completed in whole within 30 minutes:\n"
"\n"
"        curl -m 1800 -y 3000 -Y 60 www.far-away-site.com\n"
"\n"
"CONFIG FILE\n"
"\n"
"  Curl automatically tries to read the .curlrc file (or _curlrc file on win32\n"
"  systems) from the user's home dir on startup. The config file should be\n"
"  made up with normal command line switches. Comments can be used within the\n"
"  file. If the first letter on a line is a '#'-letter the rest of the line\n"
"  is treated as a comment.\n"
"\n"
"  Example, set default time out and proxy in a config file:\n"
"\n"
"        # We want a 30 minute timeout:\n"
"        -m 1800\n"
"        # ... and we use a proxy for all accesses:\n"
"        -x proxy.our.domain.com:8080\n"
"\n"
"  White spaces ARE significant at the end of lines, but all white spaces\n"
"  leading up to the first characters of each line are ignored.\n"
"\n"
"  Prevent curl from reading the default file by using -q as the first command\n"
"  line parameter, like:\n"
"\n"
"        curl -q www.thatsite.com\n"
"\n"
"  Force curl to get and display a local help page in case it is invoked\n"
"  without URL by making a config file similar to:\n"
"\n"
"        # default url to get\n"
"        http://help.with.curl.com/curlhelp.html\n"
"\n"
"  You can specify another config file to be read by using the -K/--config\n"
"  flag. If you set config file name to \"-\" it'll read the config from stdin,\n"
"  which can be handy if you want to hide options from being visible in process\n"
"  tables etc:\n"
"\n"
"        echo \"-u user:passwd\" | curl -K - http://that.secret.site.com\n"
"\n"
"EXTRA HEADERS\n"
"\n"
"  When using curl in your own very special programs, you may end up needing\n"
"  to pass on your own custom headers when getting a web page. You can do\n"
"  this by using the -H flag.\n"
"\n"
"  Example, send the header \"X-you-and-me: yes\" to the server when getting a\n"
"  page:\n"
"\n"
"        curl -H \"X-you-and-me: yes\" www.love.com\n"
"\n"
"  This can also be useful in case you want curl to send a different text in\n"
"  a header than it normally does. The -H header you specify then replaces the\n"
"  header curl would normally send.\n"
"\n"
"FTP and PATH NAMES\n"
"\n"
"  Do note that when getting files with the ftp:// URL, the given path is\n"
"  relative the directory you enter. To get the file 'README' from your home\n"
"  directory at your ftp site, do:\n"
"\n"
"        curl ftp://user:passwd@my.site.com/README\n"
"\n"
"  But if you want the README file from the root directory of that very same\n"
"  site, you need to specify the absolute file name:\n"
"\n"
"        curl ftp://user:passwd@my.site.com//README\n"
"\n"
"  (I.e with an extra slash in front of the file name.)\n"
"\n"
"FTP and firewalls\n"
"\n"
"  The FTP protocol requires one of the involved parties to open a second\n"
"  connction as soon as data is about to get transfered. There are two ways to\n"
"  do this.\n"
"\n"
"  The default way for curl is to issue the PASV command which causes the\n"
"  server to open another port and await another connection performed by the\n"
"  client. This is good if the client is behind a firewall that don't allow\n"
"  incoming connections.\n"
"\n"
"        curl ftp.download.com\n"
"\n"
"  If the server for example, is behind a firewall that don't allow connections\n"
"  on other ports than 21 (or if it just doesn't support the PASV command), the\n"
"  other way to do it is to use the PORT command and instruct the server to\n"
"  connect to the client on the given (as parameters to the PORT command) IP\n"
"  number and port.\n"
"\n"
"  The -P flag to curl allows for different options. Your machine may have\n"
"  several IP-addresses and/or network interfaces and curl allows you to select\n"
"  which of them to use. Default address can also be used:\n"
"\n"
"        curl -P - ftp.download.com\n"
"\n"
"  Download with PORT but use the IP address of our 'le0' interface:\n"
"\n"
"        curl -P le0 ftp.download.com\n"
"\n"
"  Download with PORT but use 192.168.0.10 as our IP address to use:\n"
"\n"
"        curl -P 192.168.0.10 ftp.download.com\n"
"\n"
"HTTPS\n"
"\n"
"  Secure HTTP requires SSL libraries to be installed and used when curl is\n"
"  built. If that is done, curl is capable of retrieving and posting documents\n"
"  using the HTTPS procotol.\n"
"\n"
"  Example:\n"
"\n"
"        curl https://www.secure-site.com\n"
"\n"
"  Curl is also capable of using your personal certificates to get/post files\n"
"  from sites that require valid certificates. The only drawback is that the\n"
"  certificate needs to be in PEM-format. PEM is a standard and open format to\n"
"  store certificates with, but it is not used by the most commonly used\n"
"  browsers (Netscape and MSEI both use the so called PKCS#12 format). If you\n"
"  want curl to use the certificates you use with your (favourite) browser, you\n"
"  may need to download/compile a converter that can convert your browser's\n"
"  formatted certificates to PEM formatted ones. This kind of converter is\n"
"  included in recent versions of OpenSSL, and for older versions Dr Stephen\n"
"  N. Henson has written a patch for SSLeay that adds this functionality. You\n"
"  can get his patch (that requires an SSLeay installation) from his site at:\n"
"  http://www.drh-consultancy.demon.co.uk/\n"
"\n"
"  Example on how to automatically retrieve a document using a certificate with\n"
"  a personal password:\n"
"\n"
"        curl -E /path/to/cert.pem:password https://secure.site.com/\n"
"\n"
"  If you neglect to specify the password on the command line, you will be\n"
"  prompted for the correct password before any data can be received.\n"
"\n"
"  Many older SSL-servers have problems with SSLv3 or TLS, that newer versions\n"
"  of OpenSSL etc is using, therefore it is sometimes useful to specify what\n"
"  SSL-version curl should use. Use -3 or -2 to specify that exact SSL version\n"
"  to use:\n"
"\n"
"        curl -2 https://secure.site.com/\n"
"\n"
"  Otherwise, curl will first attempt to use v3 and then v2.\n"
"\n"
"  To use OpenSSL to convert your favourite browser's certificate into a PEM\n"
"  formatted one that curl can use, do something like this (assuming netscape,\n"
"  but IE is likely to work similarly):\n"
"\n"
"    You start with hitting the 'security' menu button in netscape. \n"
"\n"
"    Select 'certificates->yours' and then pick a certificate in the list \n"
"\n"
"    Press the 'export' button \n"
"\n"
"    enter your PIN code for the certs \n"
"\n"
"    select a proper place to save it \n"
"\n"
"    Run the 'openssl' application to convert the certificate. If you cd to the\n"
"    openssl installation, you can do it like:\n"
"\n"
"     # ./apps/openssl pkcs12 -certfile [file you saved] -out [PEMfile]\n"
"\n"
"\n"
"RESUMING FILE TRANSFERS\n"
"\n"
" To continue a file transfer where it was previously aborted, curl supports\n"
" resume on http(s) downloads as well as ftp uploads and downloads.\n"
"\n"
" Continue downloading a document:\n"
"\n"
"        curl -c -o file ftp://ftp.server.com/path/file\n"
"\n"
" Continue uploading a document(*1):\n"
"\n"
"        curl -c -T file ftp://ftp.server.com/path/file\n"
"\n"
" Continue downloading a document from a web server(*2):\n"
"\n"
"        curl -c -o file http://www.server.com/\n"
"\n"
" (*1) = This requires that the ftp server supports the non-standard command\n"
"        SIZE. If it doesn't, curl will say so.\n"
"\n"
" (*2) = This requires that the wb server supports at least HTTP/1.1. If it\n"
"        doesn't, curl will say so.\n"
"\n"
"TIME CONDITIONS\n"
"\n"
" HTTP allows a client to specify a time condition for the document it\n"
);
 puts(
" requests. It is If-Modified-Since or If-Unmodified-Since. Curl allow you to\n"
" specify them with the -z/--time-cond flag.\n"
"\n"
" For example, you can easily make a download that only gets performed if the\n"
" remote file is newer than a local copy. It would be made like:\n"
"\n"
"        curl -z local.html http://remote.server.com/remote.html\n"
"\n"
" Or you can download a file only if the local file is newer than the remote\n"
" one. Do this by prepending the date string with a '-', as in:\n"
"\n"
"        curl -z -local.html http://remote.server.com/remote.html\n"
"\n"
" You can specify a \"free text\" date as condition. Tell curl to only download\n"
" the file if it was updated since yesterday:\n"
"\n"
"        curl -z yesterday http://remote.server.com/remote.html\n"
"\n"
" Curl will then accept a wide range of date formats. You always make the date\n"
" check the other way around by prepending it with a dash '-'.\n"
"\n"
"DICT\n"
"\n"
"  For fun try\n"
"\n"
"        curl dict://dict.org/m:curl\n"
"        curl dict://dict.org/d:heisenbug:jargon\n"
"        curl dict://dict.org/d:daniel:web1913\n"
"\n"
"  Aliases for 'm' are 'match' and 'find', and aliases for 'd' are 'define'\n"
"  and 'lookup'. For example,\n"
"\n"
"        curl dict://dict.org/find:curl\n"
"\n"
"  Commands that break the URL description of the RFC (but not the DICT\n"
"  protocol) are\n"
"\n"
"        curl dict://dict.org/show:db\n"
"        curl dict://dict.org/show:strat\n"
"\n"
"  Authentication is still missing (but this is not required by the RFC)\n"
"\n"
"LDAP\n"
"\n"
"  If you have installed the OpenLDAP library, curl can take advantage of it\n"
"  and offer ldap:// support.\n"
"\n"
"  LDAP is a complex thing and writing an LDAP query is not an easy task. I do\n"
"  advice you to dig up the syntax description for that elsewhere, RFC 1959 if\n"
"  no other place is better.\n"
"\n"
"  To show you an example, this is now I can get all people from my local LDAP\n"
"  server that has a certain sub-domain in their email address:\n"
"\n"
"        curl -B \"ldap://ldap.frontec.se/o=frontec??sub?mail=*sth.frontec.se\"\n"
"\n"
"  If I want the same info in HTML format, I can get it by not using the -B\n"
"  (enforce ASCII) flag.\n"
"\n"
"ENVIRONMENT VARIABLES\n"
"\n"
"  Curl reads and understands the following environment variables:\n"
"\n"
"        HTTP_PROXY, HTTPS_PROXY, FTP_PROXY, GOPHER_PROXY\n"
"\n"
"  They should be set for protocol-specific proxies. General proxy should be\n"
"  set with\n"
"        \n"
"        ALL_PROXY\n"
"\n"
"  A comma-separated list of host names that shouldn't go through any proxy is\n"
"  set in (only an asterisk, '*' matches all hosts)\n"
"\n"
"        NO_PROXY\n"
"\n"
"  If a tail substring of the domain-path for a host matches one of these\n"
"  strings, transactions with that node will not be proxied.\n"
"\n"
"\n"
"  The usage of the -x/--proxy flag overrides the environment variables.\n"
"\n"
"NETRC\n"
"\n"
"  Unix introduced the .netrc concept a long time ago. It is a way for a user\n"
"  to specify name and password for commonly visited ftp sites in a file so\n"
"  that you don't have to type them in each time you visit those sites. You\n"
"  realize this is a big security risk if someone else gets hold of your\n"
"  passwords, so therefor most unix programs won't read this file unless it is\n"
"  only readable by yourself (curl doesn't care though).\n"
"\n"
"  Curl supports .netrc files if told so (using the -n/--netrc option). This is\n"
"  not restricted to only ftp, but curl can use it for all protocols where\n"
"  authentication is used.\n"
"\n"
"  A very simple .netrc file could look something like:\n"
"\n"
"        machine curl.haxx.se login iamdaniel password mysecret\n"
"\n"
"CUSTOM OUTPUT\n"
"\n"
"  To better allow script programmers to get to know about the progress of\n"
"  curl, the -w/--write-out option was introduced. Using this, you can specify\n"
"  what information from the previous transfer you want to extract.\n"
"\n"
"  To display the amount of bytes downloaded together with some text and an\n"
"  ending newline:\n"
"\n"
"        curl -w 'We downloaded %{size_download} bytes\\n' www.download.com\n"
"\n"
"MAILING LIST\n"
"\n"
"  We have an open mailing list to discuss curl, its development and things\n"
"  relevant to this.\n"
"\n"
"  To subscribe, mail curl-request@contactor.se with \"subscribe <your email\n"
"  address>\" in the body.\n"
"\n"
"  To post to the list, mail curl@contactor.se.\n"
"\n"
"  To unsubcribe, mail curl-request@contactor.se with \"unsubscribe <your\n"
"  subscribed email address>\" in the body.\n"
"\n"
 ) ;
}