Follow Techotopia on Twitter

On-line Guides
All Guides
eBook Store
iOS / Android
Linux for Beginners
Office Productivity
Linux Installation
Linux Security
Linux Utilities
Linux Virtualization
Linux Kernel
System/Network Admin
Scripting Languages
Development Tools
Web Development
GUI Toolkits/Desktop
Mail Systems
Eclipse Documentation

How To Guides
General System Admin
Linux Security
Linux Filesystems
Web Servers
Graphics & Desktop
PC Hardware
Problem Solutions
Privacy Policy




3.2.4. The most important configuration files

As we mentioned before, most configuration files are stored in the /etc directory. Content can be viewed using the cat command, which sends text files to the standard output (usually your monitor). The syntax is straight forward:

cat file1 file2 ... fileN

In this section we try to give an overview of the most common configuration files. This is certainly not a complete list. Adding extra packages may also add extra configuration files in /etc. When reading the configuration files, you will find that they are usually quite well commented and self-explanatory. Some files also have man pages which contain extra documentation, such as man group.

Table 3-3. Most common configuration files

File Information/service
aliases Mail aliases file for use with the Sendmail and Postfix mail server. Running a mail server on each and every system has long been common use in the UNIX world, and almost every Linux distribution still comes with a Sendmail package. In this file local user names are matched with real names as they occur in E-mail addresses, or with other local addresses.
apache Config files for the Apache web server.
bashrc The system-wide configuration file for the Bourne Again SHell. Defines functions and aliases for all users. Other shells may have their own system-wide config files, like cshrc.
crontab and the cron.* directories Configuration of tasks that need to be executed periodically - backups, updates of the system databases, cleaning of the system, rotating logs etc.
default Default options for certain commands, such as useradd.
filesystems Known file systems: ext3, vfat, iso9660 etc.
fstab Lists partitions and their mount points.
ftp* Configuration of the ftp-server: who can connect, what parts of the system are accessible etc.
group Configuration file for user groups. Use the shadow utilities groupadd, groupmod and groupdel to edit this file. Edit manually only if you really know what you are doing.
hosts A list of machines that can be contacted using the network, but without the need for a domain name service. This has nothing to do with the system's network configuration, which is done in /etc/sysconfig.
inittab Information for booting: mode, number of text consoles etc.
issue Information about the distribution (release version and/or kernel info). Locations of library files.
lilo.conf, silo.conf, aboot.conf etc. Boot information for the LInux LOader, the system for booting that is now gradually being replaced with GRUB.
logrotate.* Rotation of the logs, a system preventing the collection of huge amounts of log files.
mail Directory containing instructions for the behavior of the mail server.
modules.conf Configuration of modules that enable special features (drivers).
motd Message Of The Day: Shown to everyone who connects to the system (in text mode), may be used by the system admin to announce system services/maintenance etc.
mtab Currently mounted file systems. It is advised to never edit this file.
nsswitch.conf Order in which to contact the name resolvers when a process demands resolving of a host name.
pam.d Configuration of authentication modules.
passwd Lists local users. Use the shadow utilities useradd, usermod and userdel to edit this file. Edit manually only when you really know what you are doing.
printcap Outdated but still frequently used printer configuration file. Don't edit this manually unless you really know what you are doing.
profile System wide configuration of the shell environment: variables, default properties of new files, limitation of resources etc.
rc* Directories defining active services for each run level.
resolv.conf Order in which to contact DNS servers (Domain Name Servers only). Main config file for the Sendmail server.
services Connections accepted by this machine (open ports).
sndconfig or sound Configuration of the sound card and sound events.
ssh Directory containing the config files for secure shell client and server.
sysconfig Directory containing the system configuration files: mouse, keyboard, network, desktop, system clock, power management etc. (specific to RedHat)
X11 Settings for the graphical server, X. RedHat uses XFree, which is reflected in the name of the main configuration file, XFree86Config. Also contains the general directions for the window managers available on the system, for example gdm, fvwm, twm, etc.
xinetd.* or inetd.conf Configuration files for Internet services that are run from the system's (extended) Internet services daemon (servers that don't run an independent daemon).

Throughout this guide we will learn more about these files and study some of them in detail.

Introducing Linux
Previous Page Home Next Page

  Published under the terms of the GNU General Public License Design by Interspire