/etc
is one of
UNIX® systems' most essential directories because it contains all
the host-specific 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:
passwd
and
shadow
: these are text files which contain all
system users and their encrypted passwords. You will only see
shadow
if shadow passwords are used, which
happens to be the default installation option for security
reasons.
inittab
: this is the
configuration file for init which plays a
fundamental role in starting up the system.
services
: this file
contains a list of existing network services.
profile
: this is the
shell
system-wide configuration file. Its settings can
be overridden by shell
-specific configuration files. For
example, .bashrc
for the bash
shell
.
crontab
: the
configuration file for cron, the program
responsible for periodic execution of commands.
Certain sub-directories 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.