#!/usr/bin/perl

use strict;
use warnings;

use Data::Dumper;

my @filtered;
/^hallo/i and chomp and push @filtered, [$., $_] while (<DATA>);
die Dumper \@filtered;

__DATA__
wgoiugwbuog
Hallo Welt
buwgug
fqwgiigop
hallo echo
Hallo Otto
wggoiw
wgoo