How To Set Environment Variables In Linux Using Bash

Environment variables are an important part of Linux and Bash scripting. They are used to store system-wide or user-specific values that can be accessed by commands, shells, applications, and scripts. If you are learning Bash scripting, understanding environment variables will help you write better automation scripts and manage Linux systems more effectively.

Environment variables are commonly used to store paths, usernames, language settings, configuration values, API keys, and tool settings. In cybersecurity and Linux administration, they are useful for automation, custom tool paths, temporary settings, and script configuration.

What Are Environment Variables In Linux?

An environment variable is a named value available to the shell and its child processes. For example, Linux uses variables like HOME, USER, PATH, and SHELL.

You can view some common environment variables using:

echo $HOMEecho $USERecho $SHELLecho $PATH

Example output:

/home/kalikali/bin/bash/usr/local/bin:/usr/bin:/bin

Here, HOME shows the user’s home directory, while PATH tells Linux where to search for executable commands.

How To View Environment Variables

To list all environment variables in Linux, use:

printenv

You can also use:

env

To search for a specific variable, use grep:

printenv | grep HOME

This is useful when checking system settings or debugging Bash scripts.

How To Create A Temporary Environment Variable

You can create a temporary environment variable using the export command.

Example:

export SITE_NAME="Kali Linux Tutorials"

Now print the variable:

echo $SITE_NAME

Output:

Kali Linux Tutorials

This variable is temporary. It will work only in the current terminal session. Once you close the terminal, it will be removed.

How To Use Environment Variables In Bash Scripts

Create a script:

nano env-example.sh

Add the following code:

#!/bin/bashecho "Website Name: $SITE_NAME"echo "Current User: $USER"echo "Home Directory: $HOME"

Save the file and run it:

chmod +x env-example.sh./env-example.sh

If SITE_NAME was exported earlier, the script can access it.

How To Set Permanent Environment Variables

To make an environment variable permanent for a user, add it to the .bashrc file:

nano ~/.bashrc

Add this line at the bottom:

export SITE_NAME="Kali Linux Tutorials"

Save the file, then reload .bashrc:

source ~/.bashrc

Now check the variable:

echo $SITE_NAME

This variable will be available every time you open a new terminal.

Conclusion

Environment variables in Linux are useful for storing configuration values that can be used by Bash scripts, commands, and applications. You can view them using printenv, create temporary variables using export, and make them permanent by adding them to .bashrc.

For Bash scripting beginners, environment variables are important because they make scripts more flexible and reusable. They are widely used in automation, Linux administration, and cybersecurity workflows.