Basics to Bash Scripting for Network Engineers

The trend of the engineering profession is quite old, however, many youngsters even today wish to become engineers whether it be network engineers or software engineers. Since the arrival of video games and digitalization has changed the way of life, a large number of people desire to learn codes. Though it isn’t an easy task like playing video games to do coding. A lot of hard work, dedication, passion, knowledge, and time is required to become a successful engineer. Therefore, today, we will learn about the basics of bash scripting for network engineers.

Before learning about bash scripting, let’s understand each term Bash and Script in detail to correctly learn the basics of network engineering. Let’s start!

Definition of Bash

The acronym for the language is ‘Bourne-Again Shell’. Bash is a command language interpreter. It’s available on a wide range of systems, and on GNU/Linux it acts as the default command interpreter. Bash scripts are text files with a set of commands inside.

Almost all of the features of the C shell csh and the Korn shell ksh are incorporated into bash without disabling them.

Definition of Script

A script is a set of instructions for an appropriate runtime environment that is used for automating processes and procedures. Generally, a script doesn’t require the compilation step and is rather interpreted. Complex systems can be glued together with new functions introduced by it. The sole purpose of scripting is to integrate as well as communicate with other programming or coding languages.

What is Bash Scripting

Bash is the operating system’s command language, used at the extreme level for system administration, data crunching, and development. For instance, Linux and Unix system administrators, network engineers, developers, and scientists utilize it for their work.

Bash Script is a simple plain text file that lists a collection of commands that can be executed in the command line. They are used for executing repeated tasks on the Linux filesystem. It can contain one or more commands or contain imperative programming constructs, such as loops, functions, or conditionals. It is effectively a computer program written in the Bash language, depending on its complexity and usage.

How to Make and Run Bash Script?

First, change the directory where you plan to save the script using the cd command. Once the directory is changed, type shell commands in a text editor like gedit.

By using the touch command, you can create a script that is zero bytes in size.

Follow these steps to run Bash Script: -

touch file_name

Type the following commands to open the script in a text editor (e.g., gedit):

gedit file_name.sh

The .sh extension is to provide you with the shell commands that you must type in terms of bash shell commands in the newly opened text box or text editor. Before typing any bash shell commands, first, check the base of the bash script.

Scripts based on Linux’s Bash command line begin with the following line:

SheBang (#!)

The script SheBang (#!) begins with the number sign (#) and exclamation mark (!).

When a Unix-like operating system runs a script with a shebang as a program, the first line of the script is parsed by the program loader as an interpreter directive. SheBang, therefore, stands for an interpreter that executes the script lines, and it is known as the path directive for executing various kinds of Scripts, such as Bash and Python.

For the Bash script, here is the correct SheBang format.

#!/bin/bash

It is extremely important to format the SheBang correctly. An incorrectly formatted SheBang can cause commands not to work as expected. You should only consider these two points when creating a script as follows:

The path to the interpreter must appear at the beginning of the script;

there is no space between the hash (#), and the exclamation mark prior to the path (#!).

echo

echo is a built-in command in Bash that shows standard output without regard to the arguments. It is the most widely used command for printing Strings to the screen. It performs the same way on both platforms: the shell and CLI.

Conclusion

Whether you’re a skilled network engineer or just entered this field, try the above-mentioned method to learn bash scripting. We have elaborated all the major and minor aspects of bash in detail to make it convenient for all the network engineers to learn to code for Bash.

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