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

package main;

my $name = `basename "$0"`;     # Get this script's name
$name =~ s/\R//g;               # Chop off trailing newlines

print "Script name is:  \"$name\".\n";

my $dirPerl = "/usr/bin/perl";
my $psCmd = "ps -ef | grep $name";
my $scriptRunningCount = 0;

my $output = qx($psCmd);        # Run "ps -ef | grep SCRIPTNAME"
foreach my $line (split /[\r\n]+/, $output) {
        if( index($line,$dirPerl) != -1  &&  index($line,$name) != -1 ){
                $scriptRunningCount++;
        }
}

if($scriptRunningCount == 1){
        # ...run script...
}

print "END OF PROGRAM.\n";