Variables

Variables are the containers which store data or a useful piece of information as the value inside them.

Variable-name="Variable-value"

Set variable name="DevOps"

#!/bin/bash

# Variable set
name=”DevOps”

# Print value
echo “$name”

Variable is known as the temporary storage for any kind of data like integer, float, char, etc.

A variable name can include alphabets, digits, and underscore, and its name can be started with alphabets and underscore only.

System Variables

These are the pre-defined variables as they are created and maintained by the LINUX operating system itself.

Their standard convention is that generally they are defined in capital letters, i.e., UPPER_CASE.

So whenever you see a variable defined in upper cases, most likely, they are the system-defined variables.

$PWD

Sample Script

#!/bin/bash
echo $HOME
echo “$HOSTNAME”
echo “$UID”

Export Variables

export command makes the variable available to all the subsequent commands executed in that shell.

export name=”devops”

Sample Script

It changes your terminal name into DevOps Engineer.

export ps1=”DevOps Engineer$”