#!/usr/bin/perl
use strict;use warnings;

my $string = $ARGV[0];
my $test = $string;
my @illegal = qw(\ * ?);
my @legal = qw(bs a q);
my $c = 0;
foreach my $val (@illegal) {
    $test =~ s/\Q$val\E/[$legal[$c]]/g;
    $c++;
}
print $test."\n";
[download]

$ perl ./qt.pl 'a\\b\\c\d\\\\e'
a[bs][bs]b[bs][bs]c[bs]d[bs][bs][bs][bs]e
$ perl ./qt.pl 'foo*bar\eleven?three'
foo[a]bar[bs]eleven[q]three
$
[download]

Really?! Buggers... so it will work that way. To find time to work on the problem, I simply scanned through the file until I found a section causing the headache and copied it into a perl file and assigned it to a variable (too lazy to create a file, open then read it I guess). Then I moved the sample+Perl file to a different computer (my laptop) so I can work away from the main computer.

I'll read it directly from a file and see how it goes.

You might like the __DATA__ section:

use strict;
use warnings;

foreach (<DATA>) {
    chomp;
    print "$_\n";;
}
__DATA__
illegal\characters*example?
ab\delta.txt
ab*delta.txt
[download]

Which produces

illegal\characters*example?
ab\delta.txt
ab*delta.txt
[download]