The CPAN module Proc::ProcessTable does all the parsing for you. Here is an example from the readme:

 # kill memory pigs
 use Proc::ProcessTable;

 $t = new Proc::ProcessTable;
 foreach $p ( @{$t->table} ){
    if( $p->pctmem > 95 ){
       $p->kill(9);
    }
 }
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-Mark