mjhjmtu

I'm really new to Unix and I can't figure out what this command does. From what I understand, it sends an HTTP POST request to a website. I don't know exactly what each line is supposed to do. What is the function of each line?

Here's the command:

curl http://www.example.com/xmlrpc.php -d 
 '
 pingback.ping
 http://destination.site.com/

 http://www.example.com/
 '

This is most likely a Wordpress website. The xmlrpc.php script is a PHP script that provides remote procedure calls (hence the rpc in the name) which allow you to run things on the server. These are just like methods in a Class.

Examples

<?xml version="1.0"?>
<methodCall>
 <methodName>pingback.ping</methodName>
 <params>
 <param>
 <value><string>http://.source./</string></value>
 </param>
 <param>
 <value><string>http://.target./</string></value>
 </param>
 </params>
</methodCall>

When you call the URL in your example, you're calling the pingback.ping method and providing the URLs after the call as arguments to this method. The 1st URL is the source URL of the pingback while the 2nd is the target URL.

curl's -d switch

From curl's man page:

-d/--data <data>
 (HTTP) Sends the specified data in a POST request to the HTTP server, 
 in a way that can emulate as if a user has filled in a HTML form and 
 pressed the submit button. Note that the data is sent exactly 
 as specified with no extra processing (with all newlines cut off). 
 The data is expected to be "url-encoded". This will cause curl to pass 
 the data to the server using the content-type 
 application/x-www-form-urlencoded. Compare to -F/--form. If this 
 option is used more than once on the same command line, the data 
 pieces specified will be merged together with a separating &-letter. 
 Thus, using ’-d name=daniel -d skill=lousy’ would generate a post 
 chunk that looks like ’name=daniel&skill=lousy’.

 If you start the data with the letter @, the rest should be a 
 file name to read the data from, or - if you want curl to read the 
 data from stdin. The contents of the file must already be 
 url-encoded. Multiple files can also be specified. Posting data from a 
 file named ’foobar’ would thus be done with --data @foobar".

 To post data purely binary, you should instead use the --data-binary 
 option.

 -d/--data is the same as --data-ascii.

 If this option is used several times, the ones following the first 
 will append data.