SYSTEM ENVIRONMENT SETTING IN LINUX

System environmental settings

•       The following are files those deals with system environmental settings.

•        /etc/motd : This file contains the message that users see every time they log

                example

                                 # vi /etc/motd

                                WELCOME TO TECH SOLUTION COMPUTER INSTITUTE

                                FOR BSC-IT / CS / COMMERCE / ENGINEERING /

                                FOR CERTIFICATION COURSE :- RHCE / SCJP /DOT NET / PHP / CCNA

NOTE :- LOG OUT AND LOGIN TEXT MODE AND SEE THE MESSAGE AFTER LOGIN.

•      /etc/  DIR_COLORES : this file enable you to view file listing in color.

                default color for directories are dark blue, executable file green, regular file are white

•        /etc/Issue : Whatever is in this file shows up as  a prelogin banner on your console.

•        /etc/Issue.net : This file generally contains the same thing as /etc/issue. It shows up when you attempt to telnet into the system.

•        /etc/aliases: /etc/aliases is the email aliases file for the Sendmail program, and Postfix uses /etc/postfix/aliases

•        For example root user mail box can be alias as

•        root:  sandeep

•        Root: techsolution@tyit.com

•        /etc/fstab: fstab contains important information about your file systems, such as what file system type the partitions are, where they are located on the hard drive, and what mount point is used to access them.

•        /etc/grub.conf : The /etc/grub.conf file is a symbolic link to the actual file that is located in /boot/grub/grub.conf file.

•       /etc/ cron files : cron is a daemon that executes commands according to a preset schedule that user defines. It wakes up every minute and checks all cron files to see what jobs need to be run at that time.

•        User crontab files are stored in /var/spool/cron/.

•        System cron files are stored in /etc directory.

•        System cron files are stored in /etc directory.
cron.d, cron.daily, cron.hourly ,cron. monthly, cron. weekly

•        Syslog.conf:  This daemon logs any notable events on your local system. It can store logs in a local file or send them to a remote log host for added security. It can also accept logs from other machines when acting as a remote log host. These options and more, such as how detailed the logging should be are set in the syslog.conf file.

•        Authentication previlege messages contain somewhat sensitive information so they are logged to /var/log/secure. That file can be read by root only, whereas /var/log/messages is sometimes set to be readable by everyone .

•        Id.so.conf : This configuration file is used by idconfig, which configures dynamic linker runtime bindings. It contains a listing of directories that hold shared libraries. Shared library files typically end with .so, whereas static library files typically end with .a indicating they are an archive of objects.

Logrotate.conf :  logrotate.conf and the files within the logrotate.d directory determine how often your log files are rotated by the logrotate program. Log rotation refers to the process of deleting older log files and replacing them with more recent ones. logrotate can automatically rotate, compress, remove, and mail your log files. Log files can rotated based on size or on time, such as daily, weekly or monthly