<oerjan> learn print_args_or_input Is a utility command that makes it easy to create a shell script that can be used either as a pipe or directly as a HackEgo command. Use as print_args_or_input "$@" | yourShellCode . See also shebang_args_or_input.

#!/bin/sh
exec perl '-ne/Scheme$/&&push@p,$p;$p=$_}{print$p[rand@p]' share/mtg/allsets.txt