in reply to Ensuring only one copy of a perl script is running at a time

File::Pid may be helpful to you.

Also, merlyn wrote Highlander: one instance at a time (Oct 00). Although it does use flock

I'll skip the ever-so-tempting OS trolling ...

@_=qw; ask f00li5h to appear and remain for a moment of pretend better than a lifetime;;s;;@_[map hex,split'',B204316D8C2A4516DE];;y/05/os/&print;

In Section Seekers of Perl Wisdom