use File::Pid;

  my $pidfile = File::Pid->new({
    file => '/some/file.pid',
  });

  $pidfile->write;

  if ( my $num = $pidfile->running ) {
      die "Already running: $num\n";
  }

  $pidfile->remove;

new

  my $thisfile = File::Pid->new({
    file => '/var/run/daemon.pid',
  });

  my $thisfileandpid = File::Pid->new({
    file => '/var/run/daemon.pid',
    pid  => '145',
  });

This constructor takes two optional paramters.

"file" - The name of the pid file to work on. If not specified, a pid file located in "File::Spec->tmpdir()" will be created that matches "(File::Basename::basename($0))[0] . '.pid'". So, for example, if $0 is ~/bin/sig.pl, the pid file will be /tmp/sig.pl.pid.

"pid" - The pid to write to a new pidfile. If not specified, $$ is used when the pid file doesn't exist. When the pid file does exist, the pid inside it is used.

file

Accessor/mutator for the filename used as the pid file.

pid

Accessor/mutator for the pid being saved to the pid file.

write

Writes the pid file to disk, inserting the pid inside the file. On success, the pid written is returned. On failure, "undef" is returned.

running

Checks to see if the pricess identified in the pid file is still running. If the process is still running, the pid is returned. Otherwise "undef" is returned.

remove

Removes the pid file from disk. Returns true on success, false on failure.

program_name

  Copyright (c) 2005 Casey West.  All rights reserved.
  This module is free software; you can redistribute it and/or modify it
  under the same terms as Perl itself.