use strict;
my $BasePath = '\\DirA\DirB\DirC';
my $CurrentPath = '\\DirA\DirB\DirC\DirD\DirE';

$BasePath =~ s/\x5c/\x0d/g;
$CurrentPath =~ s/\x5c/\x0d/g;

$CurrentPath =~ s/$BasePath//;

$CurrentPath =~ s/\x0d/\x5c/g;

print "\n\$CurrentPath: ".$CurrentPath."\n";