#!/usr/bin/perl -w

use strict;
my $file = 'c:/test.pl';
my @file = get_file($file);
my @results = grep { /my/ } @file;

# the grep is equivalnet to this code
# foreach $line (@file) {
#    push @results, $line if $line =~ m/my/;
# }

set_file( 'c:/results.txt', @results );
exit;

sub set_file {
    my $file = shift;
    open FILE, ">$file" or die "Oops can't write $file $!\n";
    print FILE @_;
    close FILE;
}

sub get_file {
    my $file = shift;
    open FILE, $file or "Oops can't read $file: $!\n";
    my @content = <FILE>;
    close FILE;
  return @content;
}