By the way:
- Oil has set -euo pipefail on by default. (And also nullglob)
- Oil doesn't split words by default, so you don't need the quotes: https://www.oilshell.org/release/0.8.0/doc/simple-word-eval....
Those are all "opt in" -- OSH still runs POSIX shell scripts, if you want all the extra ceremony :)