Re: runlevels

["Michael D. Norwick" <mnorwick@centurytel.net>]

ChadDavis wrote:
> 'dude' ? is that me?  I do know what runlevels, sudo and su are.  As
< snip >
>>
>> The first thing 'dude' needs to do is figure out what runlevels,
>> single-user mode, and 'sudo' or 'su to root' are!
>>
>> Michael
>>
http://www.debianhelp.co.uk/runlevels.htm.

runlevel 1 is single-user mode, not non-gui mode.  On a standalone
machine, it's useful for (as was explained earlier) fixing configuration
files, compiling programs (without the overhead of X), or performing any
computationally intensive task which doesn't require X.  The power of
the command line is the beauty of Unix and Unix-like systems.

From; http://aplawrence.com/Basics/sudo.html

"First a little background. The sudo program itself is a setuid binary.
If you examine its permissions, you will see:

---s--x--x    1 root     root        81644 Jan 14 15:36 /usr/bin/sudo

That "s" means that this is a "setuid" program. You and everyone else
have execute permission on this, so you can run it. When you do that,
because it is setuid and owned by root, your effective user id becomes
root- if you could get to a shell from sudo, you effectively WOULD be
root- you could remove any file on the system, etc. That's why setuid
programs have to be carefully written, and something like sudo (which is
going to allow access to other programs) has to be especially careful.
A setuid program doesn't necessarily mean root access. A setuid program
owned by a different user would give you that user's effective id. The
sudo program can also change your effective id while it is running- I'll
be showing an example of that here."

And; http://www.iodynamics.com/education/root101.html

Since it is the aim of millions of people worldwide to get 'root' on
'your' machine, it is a privilege not taken lightly in our community.  I
understand that your original question was about run levels and I hope
the above URL made it a little clearer.  My greater concern is that you
have an appreciation for the power provided by the 'root' prompt and
develop the skills necessary to avoid abusing it.  We live in an
algorithmically dangerous world somewhat provoked by the swiss cheese
that is Windows.  If one new linux (or BSD, or Solaris) user would take
the time to learn the safe methods to elevate privileges and pass that
information on, maybe one day we could drop most of these complicated
security tools (and paranoia).

Just my 2 cents,

Michael