if you're using vim, check out the 'perldo' (:h perldo) command. something like %perldo s/(\d)/$1x$1/ge will apply the perl code to each line in the range that preceeds perldo, in the case of %, all lines. it's quite handy
perl -e"map print(chr(hex((
q{6f634070617a6d692e7273650a}=~/../g)[hex]))),
(q{375542349abb99098106c}=~/./g)"