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

my $filename = "last.pl";
open(SOMEFILE, $filename) or die "Could not open file $filename";

LINE: while (<SOMEFILE>)
{
  # if the text contains the special word, then exit the loop
  last LINE if ( /BOMB/ );
  print "LINE: $_";
}

close(SOMEFILE);