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Asked: 2011-12-10 10:15:24 +0800 CST

How can I see or change default run level?

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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?

init

4 Answers

  1. 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.

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  2. 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.

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  3. 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
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  4. 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.

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