#!/usr/bin/perl

use strict;
use warnings;

my $file = '/path/to/file';
open my $fh,'<',$file or die $!;
while(my $line = <$fh>){
    $line =~ tr/,/\t/;
    print $line;
}
close $fh;

C:\>perl -ne "tr/,/\t/; print" file.txt
test     dass
zwei     drei