Perl script to convert base64 to uuencode format and then uudecode it

#!/bin/perl -n
tr#A-Za-z0-9+/##cd;                   # remove non-base64 chars
tr#A-Za-z0-9+/# -_#;                  # convert to uuencoded format
$len = pack("c", 32 + 0.75*length);   # compute length byte
print unpack("u", $len . $_);         # uudecode and print