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

my @prints;
while (<DATA>) {
    chomp;
    $prints[--$_]="print this one";
}

open IN,  '<', 'grep' or die 'dulce et decorum est';
open OUT, '>', 'gout' or die 'dulce et decorum est';
while (<>) {
    print OUT if shift @prints
}
close IN;
close OUT;

__DATA__
1
3
5
8