Below is useful configuration files and directories in Linux. Every DBA must be aware for daily operation.
File Name | Description |
/etc/passwd | /etc/passwd file is used to keep track of every registered user that has access to a system. File that contains the following information: Username. Encrypted password. User ID number (UID) |
/etc/hosts | hosts file is an operating system file that maps hostnames to IP addresses. |
/etc/group | The /etc/group file contains basic group attributes. This is an ASCII file that contains records for system groups. Each record appears on a single line and is the following format: Name:Password:ID:User1,User2,…,User |
/etc/issue | /etc/issue is a text file which contains a message or system identification to be printed before the login prompt |
/etc/resolv.conf | The /etc/resolv.conf is resolver configuration file for Linux and UNIX like operating systems.The file /etc/resolv.conf file contains information that is read by the resolver routines the first time they are invoked by a process. |
/etc/yum.conf | The main configuration file for yum is /etc/yum.conf.The /etc/yum.conf configuration file contains exactly one [main] section. You can add many additional options under the [main] section heading in /etc/yum.conf. |
/var/log/yum.log | if you install packages using the yum command, this log stores all related information, which can be useful in determining whether a package and all components were correctly installed. |
/etc/named.conf | The /etc/named.conf file is the configuration file for named.The /etc/named.conf file establishes the server as a master, slave, or cache-only name server. |
/etc/exports | The /etc/exports file controls which file systems are exported to remote hosts and specifies options.The file /etc/exports contains a table of local physical file systems on an NFS server that are accessible to NFS clients. The contents of the file are maintained by the server’s system administrator. |
/etc/sudo.conf | /etc/sudo.conf configuration file are allowed to use the sudo command and the command is executed in the user’s shell, not a root shell. |
/etc/cups/snmp.conf | The snmp.conf file configures how the standard CUPS network backends (http, https, ipp, ipps, lpd, snmp, and socket) access printer information using SNMPv1 and is normally located in the /etc/cups directory. |
/etc/cups/cupsd.conf | The /etc/cups/cupsd.conf file contains configuration directives that control how the server functions. |
/etc/cups/subscriptions.conf | The subscriptions.conf file defines the local event notification subscriptions that are active. |
/etc/cups/printers.conf | /etc/cups/printers.conf file to store the list of available printers. This is the printer configuration file with entries for each print queue. |
/etc/cups/client.conf | The client.conf file configures the CUPS client and is normally located in the /etc/cups or ~/.cups directory. |
/etc/oracle-release | This shows you any files that might give a hint on the operating system version. |
/etc/oraInst.loc | The Oracle inventory directory is used by the installer to keep track of all Oracle products installed on the computer. The inventory directory is stored in a file called oraInst.loc. |
/etc/ntp.conf | The NTP program is configured using either the /etc/ntp.conf |
/etc/sysctl.conf | As the /etc/sysctl.conf file is used to override default kernel parameter values and therefore only contains a few of the possible parameters. |
/home/.bash_history | The bash history is a log file that contains all commands that the user executed on the Linux shell. |
/home/.bash_profile | The ~/.bash_profile file is a configuration file for configuring user environments. The users can modify the default settings and add any extra configurations in it. |
/home/.bash_logout | The ~/.bash_logout file contains instructions for the logout procedure. |
/home/.bash_login | The ~/.bash_login file contains specific settings that are executed when a user logs in to the system. |
/var/log/maillog | Stores all logs related to mail servers |
/var/log/messages | |
/var/log/cron | Stores all Crond-related messages (cron jobs), such as when the cron daemon initiated a job, related failure messages, etc. |
/etc/shadow | |
/var/log/kern | Stores Kernel logs and warning data. This log is valuable for troubleshooting custom kernels as well. |
/var/log/dmesg | Messages relating to device drivers. The command dmesg can be used to view messages in this file. |
/var/log/faillog | Contains information all failed login attempts, which is useful for gaining insights on attempted security breaches, such as those attempting to hack login credentials as well as brute-force attacks. |
/var/log/httpd/ | A directory containing error_log and access_log files of the Apache httpd daemon |
/var/log/boot.log | A repository of all information related to booting and any messages logged during startup. |
/var/log/syslog or /var/log/messages | General messages, as well as system-related information. Essentially, this log stores all activity data across the global system. |
List of useful configuration files and directories in linux : –
Directory | Description |
/opt | According to the Filesystem Hierarchy Standard, /opt is for “the installation of add-on application software packages |
/bin | All binaries needed for the boot process and to run the system in single-user mode, including essential commands such as cd, ls, etc. |
/boot | contains files used for system startup including the kernel |
/dev | Contains device files for all hardware devices on the system |
/etc | Files used by application subsystems such as mail, the Oracle database, etc. |
/etc/init.d | Contains various service startup scripts |
/etc/profile.d | Holds application setup scripts run by /etc/profile upon login |
/etc/rc.d | Contains subdirectories which contain run level specific scripts |
/etc/rc.d/init.d | run level initialization scripts |
/etc/rc.d/rc.d | Where ‘?’ is a number corresponding to the default run level. Contains symbolic links to scripts which are in /etc/rc.d/init.d. for services to be started and stopped at the indicated run level. |
/etc/skel | Holds example dot files used to populate a new user’s home directory. |
/etc/X11 | Contains subdirectories and configuration files for the X Window system |
/home | User home directories |
/lib | Some shared library directories, files, and links |
/mnt | The typical mount point for the user-mountable devices such as floppy drives and CDROM |
/proc | Virtual file system that provides system statistics. It doesn’t contain real files but provides an interface to runtime system information. |
/sbin | Commands used by the super user for system administrative functions |
/tmp | A standard repository for temporary files created by applications and users. |
/usr | Directory contains subdirectories with source code, programs, libraries, documentation, etc. |
/usr/bin | Contains commands available to normal users |
/usr/bin/X11 | X Window system binaries |
/usr/include | Holds include files used in C programs |
/usr/share | Contains shared directories for man files, info files, etc. |
/usr/lib | Library files searched by the linker when programs are compiled |
/usr/local/bin | Common executable application files local to this system |
/usr/sbin | Commands used by the super user for system administrative functions |
/var | Administrative files such as log files, locks, spool files, and temporary files used by various utilities |
/root | This is the home directory of root user and should never be confused with ‘/‘ |
/run | This directory is the only clean solution for early-runtime-dir problem. |
/sys | Modern Linux distributions include a /sys directory as a virtual filesystem, which stores and allows modification of the devices connected to the system. |
Hope you find it useful configuration files and directories in Linux to manage you daily jobs in Linux.