#!usr/bin/perl

use strict; # perldoc strict
use warnings; # perldoc warnings

print "type hw to print hello world script!\n:> ";

my $cmd = <STDIN>;

chomp($cmd); # perldoc -f chomp

if ( $cmd eq "hw" ){ # does $cmd contain hw?
	print "Hello, world";
}else{
	print "sorry I didn't understand the command.";
}