warning for environmental variable usage
@@ -112,8 +112,12 @@ darwin, linux, or win32.
If you use `brew-warp <https://homebrew-file.readthedocs.io/en/latest/brew-wrap.html>`_,
any environmental variables can be used.
+.. warning::
+
Environmental variables are not translated if you do not use brew-wrap or
call brew directly like ``command brew``.
+ Only ``~``, ``$HOME``, ``$HOSTNAME``, ``$HOSTTYPE``, ``$OSTYPE``, and ``$PLATFORM``
+ are translated in these cases.
e.g.
