How can I see or change default run level?

In the Linux / Unix administration handbook it mentions that you can edit the /etc/inittab file to change the run level. I don't have that file on 10.04. I Googled this and found a tip saying that file had been replaced with /etc/event.d/rc-default - however I don't have that file on my system either.

Have these been deleted or does 10.04 deal with run levels differently?

4 Answers

Yes, it deals with them differently.

To see the current (and previous) runlevel:

runlevel

To switch runlevels:

sudo init $runlevel

For example, to reboot:

sudo init 6

The init you are reading about was replaced by upstart starting with Edgy Eft 6.10; and, one of the programs provided by upstart is its own implementation of init.Here are the docs for 10.04.

To change the default runlevel, use your favorite text editor on /etc/init/rc-sysinit.conf...

sudo vim /etc/init/rc-sysinit.conf

Change this line to whichever runlevel you want...

env DEFAULT_RUNLEVEL=2

Then, at each boot, upstart will use that runlevel.

To See the Current Run Level Command:

$ who -r or $ runlevel

If you want chance the runlevel Command

$ sudo init 1 ( it will take to u single user mode)

This are differnt runlevel you can perform :

0 - System halt; no activity, the system can be safely powered down.

1 - Single user; rarely used.

2 - Multiple users, no NFS (network filesystem); also used rarely.

3 - Multiple users, command line (i.e., all-text mode) interface; the standard runlevel for most Linux-based server hardware.

4 - User-definable

5 - Multiple users, GUI (graphical user interface); the standard runlevel for most Linux-based desktop systems.

6 - Reboot; used when restarting the system.

Normally this is done by explicitly adding a number to the kernel options in the GRUB entry.

Let's say, you want to change default grub entry from default run level (5) to 3:

sudo vim /boot/grub/grub.cfg

Find a place of default boot entry, and have a look at linux line. Might look something like this:

linux /boot/vmlinuz-3.0.0-13-generic root=UUID=d07e0c99-65ba-4eda-98d8-79693dc79554 ro quiet splash vt.handoff=7

Add 3 at the end of that line:

linux /boot/vmlinuz-3.0.0-13-generic root=UUID=d07e0c99-65ba-4eda-98d8-79693dc79554 ro quiet splash vt.handoff=7 3

Try it out:

sudo reboot

You could also make use of the corresponding target of your desired runlevel. You can check which of the available target your system is running as default using:

systemctl get-default 

Supposing the graphical.target is the default, you can further check its definition and detailed information using:systemctl cat graphical.target. There are some target units tailored after the corresponding runlevels. You can find which of them are available on your system by listing them: systemctl list-unit-files -t target Suppose you want to set runlevel 2 as default, you can do this by running:

sudo systemctl set-default runlevel2.target

You should use this with caution and make sure you are not causing any issues running on the inappropriate target.