CGI

CGI (W3C)
CGI tutorial

cgi-bin/first.pl:

    #!/usr/bin/perl
    print "Content-type: text/html\r\n\r\n";
    print "Hello World.";

Normally, when a 'file.html' is requested, its content is sent back in response to your browser. However, if the file is in the 'cgi-bin' directory, then the file is executed and its standard output is sent back. Apache dos not care about the language your CGI program is written in. The file must have execute permission.

second

cgi-bin/second.pl:

    #!/usr/bin/perl
    print "Content-type: text/html\r\n\r\n";
    print "Hello World.";

third

HTML code fragment

  <form name="input" action="cgi-bin/form.tcl">
   your input
   <input type="text" name="input_1">
  </form>

cgi-bin/form.tcl:

   #!/usr/bin/tclsh
   puts "Content-type: text/html\r\n\r\n";
   puts $env(QUERY_STRING)

after you type in "yourtext" and hit carriage return
the browser sends a command: "GET cgi-bin/form.tcl?input_1=yourtext"
the webserver sets the environment variable QUERY_STRING='input_1=yourtext' and starts cgi-bin/form.tcl script