Re: run levels 1 and S

["Miquel van Smoorenburg" <miquels@cistron.nl>]

In article <[🔎] 20041215165710.GA13270@cirrus.madduck.net>,
martin f krafft  <madduck@debian.org> wrote:
>Are there any differences between the run-levels 1 and S? I know
>that S10single is not executed for S, but init spawns sulogin
>directly. Any functional differences?

Runlevel S doesn't have start/stop scripts.

Runlevel 1 is used to shutdown all current running processes.

Runlevel 1's last start action is to switch to runlevel S.

So "init S" is _very different_ from "init 1", since the first
will keep all current processes running and just spawn a shell on
the console, while the latter will terminate all running processes,
_then_ switch to runlevel S.

What about /etc/rcS.d/ you say? Well, the stuff in /etc/rcS.d
is run at "sysinit" time (which happens just _once_ after boot),
not in single user mode. The 'S' stand for sysinit, not
runlevel S.

See "man init", "man shutdown", and "man inittab".

Mike.