Understanding Linux services in detail

Unless you are running some kind of low-level embedded device on your desktop—and we strongly doubt it—your operating system manages a multitude of tasks to create a comfortable and productive environment for you. Be it Mac OS X, Linux, Windows, or FreeBSD, they all run a multitude of background programs that together provide a useful system. The same goes for server flavors of those operating systems. A background program or background process (in Unix and Linux called, fluffily, a daemon) means a program that is not attached to any input (keyboard, mouse, etc.) or output (monitor, terminal, etc.). This way, they can start working even when no one is logged in to the system and keep working when the user logs out. They can also run under the privileges of a user who can never log in to the system, making their execution much safer.

The number of services running on your Linux system will, in large part, depend on the distribution...