Here is an old brute force method, that relies on the $0 name of the script in the process table. Works on linux only. 
#!/usr/bin/perl -w
#just run it. The first time it starts the daemon. If you try to start
# it a second time, it gives an error msg. Run it with any 
# commandline argument,  
#like "k" will kill all instances of the script

use strict;
use IO::Handle;
use Proc::ProcessTable;
use Proc::Daemon;

my $t1 = new Proc::ProcessTable;
my @pids;
my $pid;
foreach my $p (@{$t1->table}){
   if($p->cmndline =~ /apache-monitor/){
        $pid = $p->pid;
        #print "$pid\n";
    push(@pids,$pid); #unless $pid == $$;
       
   }
}
###################################################
if (exists $ARGV[0]) { foreach $pid (@pids){ 
                        print "killing pid $pid\n"; 
            kill 9,$pid;
        }
}

####################################################
if ($#pids > 0) {
  print "@pids  already running!\n";
  exit;
}
####################################################

Proc::Daemon::Init;
#open(LOG,">>/var/log/apache-monitor.log") or die $!; #when run as roo
+t
open(LOG,">>/tmp/apache-monitor.log") or die $!; #for testing

while (1){
my $ok =0;
my $t = new Proc::ProcessTable;
foreach my $p (@{$t->table}){
   if($p->cmndline =~ /\/usr\/sbin\/httpd/){
      print LOG time(),' ',$p->cmndline," already running!\n";
      $ok=1;last;
   }
}
if ($ok == 0) {print LOG time(),' ',"failed!\n";}
LOG->flush;
sleep(15);
}

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I'm not really a human, but I play one on earth.
Old Perl Programmer Haiku

In reply to Re: how to exit if tool is already running by zentara
in thread how to exit if tool is already running by srikrishnan

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