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

my $output_file = '/dev/null';

my $search       = 'test 1';
my $end_of_block = '[end.message]';

open my $outfh, '>>', $output_file or die "$output_file: open failed: $!\n";

while ( my $line = <DATA> ) {
    
    if ( index( $line, $search, 0 ) >= 0 .. index( $line, $end_of_block, 0 ) >= 0 ) {
        print $outfh $line or die "$output_file: print failed: $!\n";
    }
}

close $output_file or die "$output_file: close failed: $!\n";

__DATA__
test 1 von Computer 4711
MHz = 500
RAM = 256
Screen = 17 Zoll
[end.message]
test 2 von Computer 0815
MHz = 1500
RAM = 512
Screen = 21 Zoll
[end.message]