Etc files

The /etc directory is the location on a UNIX system where system-wide configuration files and scripts are stored. Some common files in the /etc directory are:

/etc

/etc/fstab

Contains filesystem configuration information.

/etc/hosts

Configures names and aliases of IP-addresses. Fields should be separated with Tab or white space. The functionality of this file has been almost entirely replaced by the DNS protocol so a hosts file is rarely used.

/etc/inittab

Controls process dispatching. Basically the key system initialization file, since it's used by process 1, init.

/etc/lilo.conf

Is the configuration file used by the Linux Loader while booting.

/etc/modules.conf

Loads modules specific options at startup.

/etc/nologin

Is a text file that, if it exists in /etc/, will prevent non-root users from logging in. If a user attempts to login, it will be shown the contents of the file, and then be disconnected.

/etc/nsswitch.conf

Specifies how the lookup for different databases are performed and in what order. Lookups are done left to right.

/etc/printcap

Describes printers and allows dynamic addition and deletion of printers by the spooling system.

/etc/resolv.conf

Configures DNS name servers to use for hostname lookups.

/etc/shadow

stores passwords and expiry dates in encrypted form.

/etc/sysctl.conf

stores Linux system parameters to set on boot.

/etc/xinetd.conf

Contains the configuration for the extended internet services started by the xinetd command.

/etc/sysconfig

/etc/sysconfig/network

Configures the system's network. Specifies hostname and gateway.

Descriptions of all of these files are in Chapter 9 of the Universal Command Guide for Operating Systems but are not found in all distributions.