Perl プロセスの PID ルックアップの例

#! /usr/bin/perl 
use strict;
use warnings;
#usage: process_grep.pl ProcessName
exit( 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;
}