sudo -s
runs the shell specified in your $SHELL
environment variable as the superuser/root. You can specify another user using -u
.
The $SHELL
environment variable contains the path to the user's default login shell. The actual setting for the default shell program is usually in etc/passwd
. Depending on what you've done in your current session, the $SHELL
variable may not contain the shell program you're currently using. If you login automatically with zsh
for instance, but then invoke bash, $SHELL
won't change from /bin/zsh
.
Show the current user and shell program:
echo $(whoami) is logged in and shell is $0
whoami
prints out the username the user is working under.
$0
contains the name/path of the currently running program (shell program in this case).
sudo
is hardly Ubuntu-specific...