Does inittab needs system restart?

UNIX for Advanced & Expert Users
1

Hi

currently my linux instance is running in runlevel 3 ( someone has set the default to 3)

i have to change it to runlevel 5 . my question

1) does the editing of /etc/inittab needs system restart to enter runlevel 5.

2) how can we avoid system restart because if some users are logged in currently and system restart may not possible .

any help is much appreciated

2 
man telinit
3
  1. No, when you edit inittab you don't automatically have to restart. init usually will check for changes and apply those, but not a runlevel change.
  2. Simple. telinit will tell init (easy to remember, isn't it :wink: ) to change to a different run level.

See the man pages for init and inittab for more information.

4

The main difference between multiuser networked runlevels (in RHEL-based systems) are the services they launch on startup.

Runlevel 3 is virtually the same as runlevel 5 (assuming you are using default settings), except that the latter will also bring up the graphical window server (X11).

It does not need a reboot; the same way you do not reboot your computer when you start or stop a system service.

If you go from runlevel 3 to 5, it won't cause any harm to the current users or processes. However if you do it the other way around (from level 5 to level 3), all applications running on X11 will basically halt.