my $gefunden = 0;

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