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

# Example strings
my $string1 = "ABCDEFderp12345";
my $string2 = "derp";

# Find position of string2 within string1
my $strpos = index($string1, $string2);

# If $strpos is greater than zero (see perldoc index)
if ( $strpos >= 0 ){

	# Print remainder of the string
	# See perldoc length, perldoc substr
	print substr( $string1, ( $strpos + length($string2) ) );
}else{
	print "$string2 does not occur within $string1";
}