#!/usr/bin/perl

use strict;
use warnings;

while( my $line = <DATA> ){
    print $line unless $line =~ /^\/begin blubber/ .. $line =~ /^\/end blubber/;
}

__DATA__
Text
am
Anfang
/begin blubber skdjflkdsjf
sdlkfjdsk
lksjflksdj
aajjllja
/end blubber
Text
am
Ende