I'm surprised nobody mentioned using Tie::File so you can use the numeric values as array indices.

#! /usr/bin/perl -w

use strict;
use Fcntl 'O_RDONLY';
use Tie::File;


# Path to file containing lines as arg
my $linesPath = shift;

# Tie the file read-only, if you want to read only, to be safe
tie my @linesFile, 'Tie::File', $linesPath, mode => O_RDONLY
    or die "Can't open file $linesPath: $!";

while(<DATA>) {
    chomp;

    # $_ - 1, I'm assuming that the list isn't 0-based
    print "$linesFile[$_ - 1]\n";
}

untie @linesFile;

__DATA__
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