Red Hat Magazine | Understanding your (Red Hat Enterprise Linux) daemons

A Unix daemon is a program that runs in the “background,� enabling you to do other work in the “foreground,� and is independent of control from a terminal. Daemons can either be started by a process, such as a system startup script, where there is no controlling terminal, or by a user at a terminal without “tying up� that terminal as the daemon runs. But which daemons can you safely play with? Which should you leave running?

A helpful explaination of these potentially confusing programs.