Run shellcheck on every script in CI
Shell has more ways to be subtly wrong than any language people actually use, and shellcheck knows most of them: unquoted variables, [ ] versus [[ ]], $? after a pipe, and plenty more.
shellcheck scripts/*.sh .github/scripts/*It runs in a second. Most of what it finds are bugs you haven't hit yet only because no file name has had a space in it.
shellci