Added some more explanatory text about HTTP posts

        curl -d "name=Rafael%20Sagula&phone=3320780" \

                http://www.where.com/guest.cgi

  How to post a form with curl, lesson #1:

  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. -d 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.

  Example:

  (page located at 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>

  We want to enter user 'foobar' with password '12345'.

  To post to this, you enter a curl command line like:

        curl -d "user=foobar&pass=12345&id=blablabla&dig=submit"  (continues)

          http://www.formpost.com/getthis/post.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.