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

my ($command, $pathname, $value);

$command = shift @ARGV;
$pathname = shift @ARGV;
if (defined $pathname and $pathname ne '') {
       if (($command eq "set") or ($command eq "add") or ($command eq "del"))
        {
                $value = shift @ARGV;
        }
        else .....
}
...