Quick way to mangle variable names in a Perl script

perlObf.pl

#!/usr/bin/perl

# run with;
# perl perlObf.pl inputFile.pl > outpuFile.pl

use Digest::MD5 qw(md5_hex);

while( <> ) {
    while(/([\$\%\@]#?)([A-Za-z]\w+)/gm) {
	if($2 ne 'ARGV') {
	    $current = '\\'.$1.$2; $new = $1.'_'.md5_hex($2);
	    s/$current/$new/;
	}
    }
    print;
}