#!perl
use strict;
use warnings;
use if ($^O eq 'MSWin32'), 'Win32::Getppid';

my $parent;
my $invoker;


BEGIN{
  if ($^O eq 'MSWin32') {
      $parent = getppid;
      open my $cmd,"tasklist  /nh /FI \"PID eq $parent\" |" or die;
      while (<$cmd>){
            chomp;
            next if /^$/;# yes it outputs a leading empty line..
            $invoker = $1 if /^([\w\d\.]+)\W/;
      }
  }
  else {
       $parent = getppid;
       open my $cmd,"ps -p $parent|" or die;
       while (<$cmd>){
            chomp;
            next if /^[\sA-Z]+$/;# get rid of heaader: freebsd does not support no header output
            $invoker = $1 if /\s([\w\d\.]+)$/;
       }
  }
}


print "Perl (PID $$) was invoked from PID $parent ($invoker)\n";