#! /usr/bin/perl
use strict;
use warnings;
use Data::Dumper;
use utf8;

my $file = shift || die "no input file given.";

my $re_suche = qr{[äöü]}i;

# ohne ":encoding(...)" gibt es keinen Match
open my $fh, '<:encoding(UTF-8)', $file
   or die "open '$file' failed: $!\n";

while ( my $l = <$fh> ) {

    if ( $l =~ $re_suche ) {
        print "  Match\n";
    }
    else {
        print "NoMatch\n";
    }

}

close $fh;