#!/bin/bash
sed -n -r -f /dev/fd/3 3<<'EOS' "$@"
s/^	(([^$'(){}<>|;&*?`]|'[^']*'|\$[^(]|\$\([^)]*\))*)([(){}<>|;&*?`]|\$\$)(.*)$/\1SHELL!\3!\4/p
EOS