On linux, what you want to do is look thru the /proc directory. You will see directories named after the pid, containing all the info and file_descriptors for that process. Additionally, there are files in there containing system information. You can google for "linux proc" and get lots of info.

Perl has a module for looping thru it all and creating stats, it uses alot of cpu though, so often you might want to run the system utlities like 'top', and 'ps auxww', thru system.

#!/usr/bin/perl
use Proc::ProcessTable;
# Dump all the information in the current process table

$t = new Proc::ProcessTable;

while(1){
 foreach $p (@{$t->table}) {
   print "\n--------------------------------\n";
   foreach $f ($t->fields){
     print $f, ":  ", $p->{$f}, "  ";
   }
}

sleep(1);
}
[download]