Make it clear that env vars must be simple
Closes
@@ -220,7 +220,8 @@ system's interfaces.
$ docker run -e MYVAR1 --env MYVAR2=foo --env-file ./env.list ubuntu bash
-This sets environmental variables in the container. For illustration all three
+This sets simple (non-array) environmental variables in the container. For
+illustration all three
flags are shown here. Where `-e`, `--env` take an environment variable and
value, or if no `=` is provided, then that variable's current value is passed
through (i.e. `$MYVAR1` from the host is set to `$MYVAR1` in the container).
