System configuration files.

Aug 30, 2006 14:29 GMT  ·  By

I will try to list here some of the configuration files found in a Linux system, and what they are useful for:

/etc/profile - System wide environment variables for all users.

/etc/aliases - Where the user's name is matched to a nickname for e-mail.

/etc/fstab - List of devices and their associated mount points. Edit this file to add CD-ROMs, DOS partitions and floppy drives at startup.

/etc/mtab - This changes continuously as the file /proc/mount changes. In other words, when filesystems are mounted and unmounted, the change is immediately reflected in this file.

/etc/mtools.conf - Configuration for all the operations (mkdir, copy, format, etc.) on a DOS-type filesystem.

/etc/motd - Message of the day broadcast to all users at login.

/etc/rc.d/rc.local - Bash script that is executed at the end of the login process. Similar to autoexec.bat in DOS. You can put your own initialization stuff in here if you don't want to do the full Sys V style init stuff.

/etc/crontab - Lists commands and times to run them for the cron deamon.

/etc/cron.* - There are 4 directories that automatically execute all scripts within the directory at intervals of hour, day, week or month.

/etc/group - Similar to /etc/passwd but for groups rather than users.

/etc/gshadow - Used to hold the group password and group administrator password information for shadow passwords.

/etc/hosts - A list of all known host names and IP addresses on the machine.

/etc/hosts.allow - Man page same as hosts_access. Read by tcpd at least.

/etc/hosts.deny - Man page same as hosts_access. Read by tcpd at least.

/etc/httpd/conf - Paramters for the Apache web server

/etc/inittab - Specifies the run level that the machine should boot into.

/etc/resolv.conf - Defines IP addresses of DNS servers.

/etc/smb.conf - Config file for the SAMBA server. Allows file and print sharing with Microsoft clients.

/etc/passwd - The user database with fields giving the username, real name, home directory, encrypted password and other information about each user.

/etc/printcap - A configuration file for printers.

/etc/rc.d/rc0.d - Contains files used to control run level 0. Usually these files are softlink files.

/etc/rc.d/rc1.d - Contains files to control run level 1. Scripts beginning with an S are for start, K for kill.

/etc/rc.d/rc.sysinit - Init runs this when it starts.

/etc/sysconfig/clock - Used to configure the system clock to Universal or local time and set some other clock parameters.

/etc/sysconfig/i18n - Controls the system font settings.

/etc/sysconfig/init - This file is used to set some terminal characteristics and environment variables.

/etc/sysconfig/keyboard - Used to configure the keyboard.

/etc/sysconfig/network-scripts/ifcfg-interface - Defines a network interface.

/etc/X11/xorg.config - Config file for X11. Here you can setup the mouse, keyboard, monitor and video card.

/proc/cpuinfo - Information about the processor such as its type, make and performance.

/proc/devices - A list of devices configured into the currently running kernel.

/proc/dma - Shows which DMA channels are being used at the moment.

/proc/filesystems - Filesystems that are configured into the kernel. The file used to detect filesystems if the /etc/filesystems does not exist.

/proc/ioports - Shows which I/O ports are in use at the moment.

/proc/interrupts - Shows which interrupts are in use and how many of each there have been.

/proc/kcore - An image of the physical memory of the system.

/proc/kmsg - Messages output by the kernel. These are also routed to syslog.

/proc/ksyms - Symbol table for the kernel.

/proc/loadavg - The load average of the system.

/proc/meminfo - Information about memory usage, both physical and swap.

/proc/modules - Which kernel modules are currently loaded.

/proc/mounts - Contains information on filesystems currently mounted, similar to /etc/mtab

/proc/net - Contains status information about network protocols.

/proc/self - A symbolic link to the process directory of the program that is looking at /proc. When 2 process look at proc, they get different links.

/proc/stat - Various statistics about the system such as the number of page faults since the system was booted.

/proc/uptime - The time the system has been up.

/proc/version - The kernel version.