$ ps -p xxxx

  PID TTY          TIME CMD
29580 pts/4    00:00:00 bash

$ ps -p yyyy

   PID TTY      TIME CMD
  9556 pts/49   0:00 bash

##</code><code>##

my $parent = (grep {/^\s*\d+/} (`ps -p $parent_id`))[0];

##</code><code>##

my $parent = " ".(grep {/^\s*\d+/} (`ps -p $parent_id`))[0];