What are Runlevels

Question

What are runlevels in Linux?

Answer

Runlevels are how linux keeps track of what Daemons (services) should be started. The following is a list of the runlevels:

Runlevel 0:

This shuts the system down. In the process this will also unmount the file system.

This is the single user mode. In this mode, only the admin can log on. This is used for hardware configuration only.

This is multi user mode. This is the standard runlevel for a single standalong machine.

This is the standard run level for a networked linux installation.

This is a user defined run level. This means that until you add some symbolic links to the /etc/rc.d/rc4.d directory, this won't do anything.

This starts the machine with a graphical login prompt.

This restarts the machine. This is the same as calling runlevel 0, then starting up the machine into it's default runlevel.

Tags: Linux