Because /etc/profile (and ~/.profile) are read by login shells only,
aliases and functions defined there are not available to non-login
shells, e.g. when using screen or tmux.
If the ENV environment variable exists (exported by /etc/profile or
~/.profile) and references an existing file, then all interactive shells
(login or non-login) will read that file as well.
This sets the ENV environment variable in /etc/profile, pointing to
/etc/shinit.
This also adds /etc/shinit, which:
* Contains alias and function definitions originally in /etc/profile
* Sources /etc/mkshrc if the user is using mksh (also originally in
/etc/profile), as /etc/mkshrc is meant for all interactive shells
* Sources ~/.mkshrc if the user is using mksh, to compensate for the
fact that mksh will not read ~/.mkshrc if ENV is set
* Sources ~/.shinit if the user is not using mksh
This also removes the shebang from /etc/profile, as the file is sourced,
not executed.
Signed-off-by: Jeffery To <jeffery.to@gmail.com>
