use strict;
use warnings;
use feature 'say';

my %hash = (
    file0 => { opt0 => undef, opt1 => 1 },
    file1 => { opt0 => 0,     opt1 => 1 },
);

foreach my $file ( keys %hash ) {
    my %temp = %{ $hash{$file} };
    OPTION:
    foreach my $opt ( keys %temp ) {
        if (   !exists $hash{$file}
            or !exists $hash{$file}{$opt}
            or !defined $hash{$file}{$opt} )
        {
            warn "Option does not exist\n";
            next OPTION;
        }
        $hash{$file}->{$opt} =~ s/[^[:ascii:]]//gxms;
        my $lined = join( "\t", $file, $opt, $hash{$file}->{$opt} )
            . "\n";
    }
}