can someone tell me what is the different between init and telinit?

Thanks.

init is the primary process that is the parent to all other processes. It starts at boot and checks out your /etc/inittab and a bunch of other settings. It also has the notion of the runlevel and knows, from your /etc/init.d settings for instance, which processes to start/stop when you switch between runlevels.

telinit is a smaller tool that informs init when it needs to switch runlevels. So you can use "telinit" to "tell init" that it needs to switch runlevel.

A quick example:
when you boot into graphical mode (runlevel 5), init will start and launch all programs associated for runlevel 5 (itself being the parent process of all those). When you then ask to shutdown the machine, telinit will inform the -still running- init process that it needs to switch to runlevel 6 (for reboot) or 0 (for system halt).

See "man init" for details on runlevels.

From the user's point of view there is (afaik) no difference. telinit 5 and init 5 executed from the commandline will produce identical results.

er...i see.....

yeah, I wondered the same thing when i just recently dived into Slackware

I guess what timmeke and alienDog are trying to say is that telinit is a cleaner and neater solution. Running more than one init process is not nescessary and may confuse things in a ps analysis. But nevertheless, both have the same effect and you can use init is you want.

I still prefer the init system in FreeBSD over sysv or any other Linux init system for that matter. But Linux still has many advantages over FreeBSD for desktop computing. And Slackware feels the most like FreeBSD so far. Which is maybe why I'm starting to like it at the moment.

Oops, I didn't realize how old this thread was... LOL.

binary_0011: I live in Sinagpore too. At least here in 2014. Do you still live here, go to any LUG here? I find it very rare in Singapore to find someone who speaks Linux.

init is the parent process to all other process. But telinit will use init; either you have link or not - telinit has to use init. If you don't see telnet have link to init do strings command as below to understand.

# strings `which telinit` | grep init
nih_main_init_full
dbus_error_init
dbus_message_iter_init_append
dbus_message_iter_init
__libc_csu_init
telinit.c
RUNLEVEL may also be Q or q to instruct the init daemon to reload its configuration, this is rarely necessary since the daemon watches its configuration for changes.
RUNLEVEL may be U or u to instruct the init daemon to re-execute itself, this is not recommended since Upstart does not currently preserve its state.