#!/usr/bin/perl -w
use strict;

open (FILE, "file") || die "File does not exist\n";
my @file = <FILE>;
my $file = @file;
close (FILE);

open (FILE, ">file") || die "File does not exist\n";
for (my $n = 0; $n <= $file; $n++) {
  $_ = $file[$n];
  print FILE $_;
}

print "add whatever";
print "here\n";
print "to end of txt.\n";

close (FILE);