#!/usr/bin/perl use strict;use warnings;#usage: process_grep.pl  ProcessNameexit( main(@ARGV) ); sub main {  my $Phash;  my $ProcessName = shift;  my $PROC_DIR  = "/proc";  chdir $PROC_DIR;  my @pids = glob "[0-9]*";  for my $pid (@pids) {    open( FH, "$pid/cmdline" ) or die "Can't $pid file $!";    $Phash->{$pid} = $_ while <FH>;  }  delete $Phash->{"$$"};  for my $pid ( keys %$Phash ) {    print $pid, "/n" if $Phash->{$pid} =~ /$ProcessName/;  }  return 0;}