#!/usr/bin/perl -w

use strict;
use warnings;

my $path = "/Ordner/wo/alles/liegt";
my $file = "datei_mit_der_mail";

my $gefunden = 0;

open(DATA, "<$path/$file") || die "Cannot open $file file!\n";
while (<DATA>)
{
  chomp;
  $zeile = $_;
  if ( /^test1;test2;test3/ )
  {
       $gefunden = 1;
  }
  if ( $gefunden == 1 )
  {
       if ( $zeile =~ s/\=// )
       {
           print "Debug: $zeile\n";
       }
  }
}
close (DATA);