#!/bin/bash

curl "http://ftp.gnu.org/gnu/parallel/" 2> /dev/null | \
  tr "<>" "\n\n" | \
  grep "^parallel-[[:digit:]]\+\.tar\.bz2\$" | \
  sed "s/^parallel-\([[:digit:]]\+\)\.tar\.bz2\$/\1/" | \
  sort -V | \
  tail -n1