While all the scripts provided below may be accurate, there may be much more advanced features available. However, these scripts are just to give an overview of how things are meant to be done for a systems administrator. I did not make any of the below scripts and all scripts’ references are given inline along with their description.

Disk usage

This script will be useful to analyze the disk usage and if the reported disk space is more than 90 % an email will be sent to the administrator. The script is taken from here.

Incremental Backup Scripts

This script will do the incremental backup into an external mounted hard-drive. It is to take a backup of the /home directory. However, it can be modified to suit the requirements. The script is taken from here.

High CPU Usage Script

At times, we need to monitor the high CPU usage in the system. We can use the below script to monitor the high CPU usage. The script is taken from here.

Adding new users to a Linux system

This script allows the root user or admin to add new users to the system in an easier way by just typing the user name and password (The password is entered in an encrypted manner). The below script is taken from here.

Database Backup

This script is a pretty basic script useful in backing up the database. The script is taken from here.

Source : http://unix.stackexchange.com/questions/125726/important-scripts-useful-for-a-linux-system-administrator