#!/usr/local/bin/perl
use warnings;
use strict;

use Fcntl ':flock';
use Tie::File;

my $fifo = "$ENV{HOME}/a_file";
my $lock = "$fifo.lock";

tie( my @pid, 'Tie::File', $lock )->flock( LOCK_EX )
    or die "Cannot open '$lock' $!";

@pid = $$;

tie( my @lines, 'Tie::File', $fifo )->flock( LOCK_EX )
    or die "Cannot open '$fifo' $!";

( my $pop, @lines ) = sort @lines;

print "$hostname is poping $pop\n";

untie @lines;

print "PID lock file is going to be removed\n";

untie @pid;
unlink $lock or die "Cannot unlink '$lock' $!";

__END__