#!/usr/bin/perl

use warnings;
use strict;

print "Vokal in SAMPA-Zeichen eingeben: ";
chomp(my $vokal = <STDIN>);

opendir(my $fhDir, "c:\\Daten\\") or die $!;
my @files = grep { $_ =~ m/\.txt$/ } readdir($fhDir);
closedir($fhDir) or die $!;

for (my $i = 0; $i <= $#files; $i++) {

   open(my $fhEin, "<$files[$i]") or die $!;

   while(my $zeile = <$fhEin>) {

      if ($zeile =~ m/$vokal/) {
         print $files[$i]."\n";
         last;
      } # if

   } # while

   close($fhEin) or die $!;

} # for