The /etc/ directory

This page last updated 20060709

The /etc/ directory contains configuration files for the programs supported by the host. It is editing the files under /etc/ that much of the work of configuring a Linux system is done, and of course much of the work of passing the RHCT/E exams. The structure and conventions of the /etc/ directory differ between RedHat and other Linux distributions.

On my CentOS 4 system, the command

$ ls /etc | wc

yields a report showing

   287     287     2771

which reflects 287 lines containing 287 words at a total of 2771 characters, in other words 287 filenames, some of which are names of directories.

Generally, names of normal files in the top level of the /etc/ directory structure are configuration files for the system, and the names of subdirectories under /etc/ are for various daemon processes and store whatever files are needed by the daemon process. Many of the subdirectory names end with a ".d" suffix, which is a name convention to allow humans to identify directories.

$ ls -d /etc/*.d 
cron.d 
dev.d
hotplug.d
...

Note that names of daemon processes generally end with the 'd' character (not ".d").

$ ls /etc/ | grep [^.]d$ 
blikid.tab.old
httpd
motd
passwd...
vsftpd

The names httpd and vsftpd represent those daemons. Other names (motd--message of the day, passwd--password...) coincidentally end with the 'd' character.

more to come