Could crude shell scripts be used for this purpose? For example, in zsh [0]:

  $ echo "Do the first step, then press any key."; read -s -k

EDIT: Apparently so: [1]

[0] Modeled on https://stackoverflow.com/questions/5215343/how-can-i-pause-...

[1] https://news.ycombinator.com/item?id=20495739