Shell script is frequently used when monitoring system status on Linux. It's not an easy task to write shell script but it's a very important skill for developers and system administrators to ease work and automate common tasks. This post will share some common interview questions about shell script.1. Get random characters(8 characters)Method 1# echo $RANDOM |md5sum |cut -c 1-8471b94f2Method 2# openssl rand -base64 4vg3BEg==Method 3# cat /proc/sys/kernel/random/uuid |cut -c 1-8ed9e032c2. Get random numbers(8 digits)Method 1# echo $RANDOM |cksum |cut -c 1-823648321Method 2# openssl rand -...

Many people hack together shell scripts quickly to do simple tasks, but these soon take on a life of their own. Unfortunately shell scripts are full of subtle effects which result in scripts failing in unusual ways. It's possible to write scripts which minimise these problems. In this article, I explain several techniques for writing robust bash scripts. Use set -u How often have you written a script that broke because a variable wasn't set? I know I have, many ti...