Andrew Marshall wrote: > perhaps it’s worth documenting or making it an invalid config on Darwin.
We could document that users should not use environment variables that start with "__", because these environment variables can be set by the OS and can influence the behaviour of the OS. Proposed patch is attached. Once that is documented, I don't think anything is wrong with CoreFoundation setting or use any __FOOBAR environment variable(s). Bruno
>From 3291e071140b01129c0e5b57967405434b35b325 Mon Sep 17 00:00:00 2001 From: Bruno Haible <[email protected]> Date: Sun, 2 Nov 2025 10:21:15 +0100 Subject: [PATCH] env: document role of environment variables that start with __ * doc/coreutils.texi (env invocation): Document role of environment variables that start with __. --- doc/coreutils.texi | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/doc/coreutils.texi b/doc/coreutils.texi index 13f9f9a46..061228b90 100644 --- a/doc/coreutils.texi +++ b/doc/coreutils.texi @@ -18135,6 +18135,11 @@ However, it is wise to limit yourself to names that consist solely of underscores, digits, and ASCII letters, and that begin with a non-digit, as applications like the shell do not work well with other names. +Also, you should avoid environment variables with names that start +with two underscores, +@c So far, this applies only to macOS and __CF_USER_TEXT_ENCODING. +because such environment variables can be set by the operating system +or influence the behavior of the operating system. @vindex PATH The first operand that does not contain the character @samp{=} -- 2.51.0
