http://www.perlmonks.org?node_id=977387


in reply to reliable lockfiles?

Regarding the part of your comment regarding PIDs, I believe you can kill 0, $pid to determine if a signal can be sent to that PID. If so, then verify that the PID is for a process executing the same script/program (by parsing the result of a 'ps' command, or using a module such as Proc::ProcessTable).

# Untested use Proc::ProcessTable; my $tobj = new Proc::ProcessTable; my $proctable = $tobj->table(); my $pid = 0; for ( @$proctable ) { if ( $_->cmndline =~ m/$script_name/ ) { $pid = $_->pid; last; } } print $script_name, ( kill 0, $pid ? q{appears} : q{does not appear} ), q{ to be running}, qq{\n};

Hope that helps.