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

my $string = "This is what you have";

if(substr($string, -14) =~ /have/){
   print "You've already a good programmer!!\n";
}

substr($string, 0, 5) =~ s/is/at/g;
print "$string\n";

substr($string, 0, 1) ="S";
print "$string\n";