Joseph Herlant
version 1.0.0, 2014-07-04 : Initial version

runlevel and who -r commands display the current and previous runlevels.

Using shutdown now with no other option specified actually brings system in maintenance mode.

Scripts in /etc/rc.d/rc[1-6].d directories are played in the following order:

  • K* first, then S*

  • Then the order is defined by the number and then the alphabetical order of the given service name

chkconfig servicename off disables servicename service on boot.

chkconfig --level 5 servicename off disables servicename service only for runlevel 5.

To change runlevel, use telinit or init followed by the runelevel number. Example, to switch to runlevel 1, use:

telinit 1

The difference between init and telinit is that init is the parent of all processes and if it’s called by a user process, it automatically calls telinit with the same arguments it has been given.