What to do when a command isn't found?

[Al Sparks]

--- jdow <jdow at earthlink.net> wrote:
> 
> The /sbin and /usr/sbin directories are generally commands that users
> should not use and which may not work at all for users. It is a basic
> part of the security of the system. Unfettered access to ifconfig gives
> a really nice way to perform nastiness on your system by bringing up
> or down various interfaces. It's somewhat handy if commands users are
> not expected to use are not on the user's path.

I tried to execute
   ifconfig eth0 down
on my system as non-root, and got permission denied.

If you're going to restrict access to the commands in /sbin, you
should also change the permissions on the /sbin directory so
unauthorized personnel can't reach it.  As things stand now, you
simply have security through obscurity, since users can change their
own $PATH.

Actually, if you're going to restrict users, you default their shell
to /bin/rbash, set their $PATH to a small amount of directories, and
make their .bashrc and .bash_profiles inaccessible.
   === Al