#! /usr/bin/perl -w

use strict;


my $fname = "aaabbbcccddd";

# Some creepy / characters to prove the quotemeta is doing its job
my $orig = "abc/";
my $repl = "def/";


print "before: $fname\n";

$_ = $fname;
eval sprintf "tr/%s/%s/", map quotemeta, $orig, $repl;
$fname = $_;

print "after: $fname\n";

=for explain

The eval line above was confusing to me at first (and I'm not even
a total newbie). It may help to see it delimited with more 
parenthesis:

eval (sprintf ("tr/%s/%s/", map (quotemeta, $orig, $repl)));


From right to left:

The map uses quotemeta as its EXPR and $orig, $repl as its input list
quotemeta is operating on a local $_

The two variables sprintf is expecting are in the list output from map

eval is evaluating the resulting string made by sprintf. The tr/// is
operating on $_

=cut