How to Set an Environment Variable in Linux

Environment variables store temporary data like paths, configuration settings, and tokens. Programs and scripts access these values without hardcoding them into files. This guide shows how to set an environment variable in Linux for current sessions and across system restarts.

What Are Environment Variables in Linux

Environment variables store system and user configuration data. Each user has a unique set of variables that define their working environment. An admin account differs from a standard user account in terms of available variables and permissions.

Variables can be user-specific or system-wide. Examples include personal API keys visible only to one user or global paths accessible to all users.

Common environment variables:

Variable	Description
USER	Current logged-in username
HOME	User home directory path
SHELL	Active shell path like bash or zsh
LANG	System language and locale settings
MAIL	User mailbox location
PATH	Directories searched for executables

These variables exist only for the current session unless configured for persistence.

How to List Environment Variables in Linux

Display all environment variables for your session:

$ env

Output shows all defined variables:

SHELL=/bin/bash
PWD=/home/user
USER=user
HOME=/home/user
LANG=C.UTF-8
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
MAIL=/var/mail/user

How to Print Environment Variables in Linux

Two methods display specific variable values.

Using printenv Command

Print a single variable:

$ printenv SHELL

Returns:

/bin/bash

Using echo Command

Print using the dollar sign prefix:

$ echo $SHELL

Returns:

/bin/bash

Both methods produce identical output. The echo command requires the dollar sign before the variable name.

How to Set Environment Variables in Linux

Use the export command to define variables:

$ export JAVA_HOME=/usr/bin/java

Verify the variable exists:

$ echo $JAVA_HOME

Returns:

/usr/bin/java

Variables set this way exist only in the current session. Close the terminal and the variable disappears.

How to Make Environment Variables Persistent in Linux

Store variables in configuration files to preserve them across sessions.

Edit .bashrc for User Variables

Open the .bashrc file in your home directory:

$ vi ~/.bashrc

Add the export statement at the end:

export JAVA_HOME=/usr/bin/java

Apply changes without logging out:

$ source ~/.bashrc

Test by opening a new terminal:

$ echo $JAVA_HOME

The variable persists across all future sessions for your user account.

How to Create a Global Environment Variable in Linux

Global variables are accessible by all users on the system. Define them in system-wide configuration files.

Using /etc/environment

Edit the file with root privileges:

# vi /etc/environment

Add the variable without using export:

GLOBAL_VARIABLE="This is a global variable"

Apply changes:

# source /etc/environment

Using /etc/profile

Edit the profile file:

# vi /etc/profile

Add the variable with export:

export GLOBAL_VARIABLE="This is a global variable"

Test from any user account:

$ echo $GLOBAL_VARIABLE

Returns:

This is a global variable

All users can now access this variable regardless of their session.

How to Verify Environment Variables Work

Check if a variable persists across sessions:

Open a new terminal window.

Print the variable:

$ echo $JAVA_HOME

If the output shows the value, the variable is persistent. Empty output means the variable was not saved correctly or the configuration file was not sourced.

Verify global variables by switching users:

$ su - username
$ echo $GLOBAL_VARIABLE

The variable should display for all user accounts.