What are and how to change Runlevels
Monday, March 24th, 2008
Many people get confused when trying to boot in to a runlevel other than runlevel 5, for example runlevel 3, disabiling the GUI front end with which most users are familiar. Hopefully this howto will help answer the questions “How do I disable X” or “How do I boot without X” or even “How do I get to single user mode.”
One requirement of this is to have an understanding of what runlevels are, how changing runlevels will impact your system, and what services may or may not be started. In general this is beyond the scope of this document but I will give a quick run down of things as listed in /etc/inittab.
Just a warning, this does not apply to Ubuntu as Ubuntu focuses on Upstart.