de.yahoo.com
mail.example.org
www.aol.com
www.example.org
www.freshmeat.net
www.hotdoggie.com.au
##</code><code>##

www.hotdoggie.com.au
www.aol.com
de.yahoo.com
www.freshmeat.net
mail.example.org
www.example.org
##</code><code>##

cat foo | perl -ple'$_=join".",reverse split/\./' | sort | \
          perl -ple'$_=join".",reverse split/\./'
# or
alias tldmunge='perl -ple'"'"'$_=join".",reverse split/\./'"'"
cat foo | tldmunge | sort | tldmunge