/etc/: Configuration Files

/etc/ is one of UNIX systems' most essential directories because it contains all the basic system configuration files. Never delete it to save space! Likewise, if you want to extend your tree structure over several partitions, remember that /etc/ must not be put on a separate partition: it is needed for system initialization and must be on the root partition at boot time.

Here are some important files:

Certain subdirectories exist for programs which require a large number of configuration files. This applies to the X Window System, for example, which stores all of its configuration files in the /etc/X11/ directory.