Understand basic concept of programming also what are the advanced feature of BASH. eduCBA brings you this amazing course on Linux Bash Scripting, in which any beginner will be able to understand all the concepts.
Bash scripting is nothing but the combining multiple simple tools to solve a more complex problem, usually using pipes to direct the output of one command to the input of the next. This is a style of programming which is worth knowing; too many people write a whole program to achieve something that can be done by combining a few existing tools on the command line.
If you want to work as a system admin then you should know how to write bash script. Today most of the IT companies uses LINUX/UNIX servers so to work on those server you should know BASH scripting.