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Table of contents
1.
Introduction
2.
Overview of Linux Environment
2.1.
Computing Environment 
2.2.
Variables
2.3.
Linux Environment Variables
2.4.
Scope of Linux Environment Variables
3.
Common Linux Variables
4.
Working with Environment Variables
4.1.
Accessing the Linux Environment Variables
4.2.
Setting New Environment Variables
4.3.
Deleting Linux Environment Variables
5.
Frequently Asked Questions
5.1.
How long can a Linux Environment variable be?
5.2.
What purpose do Linux environment variables serve?
5.3.
In Linux, how do I set several environment variables?
5.4.
In Linux, how can I make a temporary environment variable?
5.5.
How is an environment variable removed?
6.
Conclusion
Last Updated: Mar 27, 2024
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Linux Environment

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Introduction

Welcome Ninjas!

This blog will discuss an essential Linux/Unix concept, the Linux Environment. The Linux Environment variables define the Linux Environment. The user sets some variables, some by the system and others by programs or the Shell.

Introduction

We hope you are very excited to see how Linux Environment works, so let’s dive into the concepts of the Linux Environment.

Overview of Linux Environment

This section will guide you through the essential components of the Linux Environment, which will let you understand the commands explained in the other part of the blog more clearly.

Computing Environment 

The platform (Platform = Operating System + Processor) in which a user can run programs is known as the computing environment.

Variables

A variable in computer science is a place to store a value, which can be a filename, text, integer, or any other type of data. It is frequently referred to by the symbolic name assigned at creation. The value thus saved may be seen, removed, modified, and saved again.

Because they allow programmers to create flexible programs, variables are crucial in computer programming. It is essential to understand some of them and how we might impact them because they are connected to the Operating system on which we work.

Linux Environment Variables

Linux Environment variables

Environment variables are dynamic values that influence a computer's processes or applications. Every operating system has these; however, the types can change. Environment variables provide the system's operation details and can be generated, updated, saved, and deleted.

Environment variables have the power to alter how software and programs operate.

Scope of Linux Environment Variables

Any variable's scope refers to the area from which it can be accessed or the area across which it is defined. In Linux, an environment variable may have either a global or local scope.

Global

Access to a globally scoped ENV defined in a terminal is possible from any location within the terminal's environment. It can be used in scripts, applications, or processes tied to the environment by that terminal.

Syntax to set global Env:

$ export NAME=Value


or

$ set NAME=Value


Where NAME is the name of the global variable and value is its value.

Global ENV variable
Alternate way for Global env variable

Local

Any program or process executing in the terminal cannot access a locally scoped ENV that is defined there. Only the terminal (in which it was defined) itself has access to it.

Syntax to set local Env:

$ NAME=Value
Local ENV
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Common Linux Variables

We present to you a list of standard Linux Environment variables:

Variable

Meaning

PATH

This variable holds a list of directories where your system looks for executable files, separated by colons (:).

When you type a command into the terminal, the Shell searches the various folders listed in the $PATH variable for the command. The order is carried out if it is located. If not, it returns the message "command not found."

USER This represents the username.
EDITOR Represents the path to the program that edits the contents of the files.
HOME This means the default path to the home directory of the user.
SHELL Represents the shell that the user is using.
UID This is a user’s unique ID.
TERM It is the default terminal emulator.
LANG It represents the current locale setting.
MAIL Represents the location of storage of user mail.
PWD It gives the path of the current working directory.

 

Working with Environment Variables

In this section, we will explore the commands required to work with the environment variables. We will execute them in the Linux environment to better understand them.

Accessing the Linux Environment Variables

Syntax to access variable values:

echo $VARIABLE


Below is an example of some Environment variables:

Accessing variable

The env command displays all the Linux environment variables.

Displaying all variables

Setting New Environment Variables

The syntax to set a new Linux  Environment Variable is

VARIABLE_NAME= variable_value


Things to keep in mind:

  • The variable names are case-sensitive and are preferably created in upper-case.
  • Do not leave space between “=” and value.
  • Do not forget the “$” sign when you check the variable's value.
Setting new environment variable

Deleting Linux Environment Variables

The syntax to delete the Linux Environment Variables is:

unset Variable_name


Let us delete the variable we created in the example above.

Deleting Environment variable

Frequently Asked Questions

How long can a Linux Environment variable be?

An environment variable can have a maximum theoretical length of about 32,760 characters. You're not likely to reach that theoretical maximum, though. A single environment block must contain all environment variables, which can only include 32767 characters.

What purpose do Linux environment variables serve?

Environment variables, or ENVs, essentially dictate how the environment behaves. They may have an impact on running processes or running programs in the environment.

In Linux, how do I set several environment variables?

You can modify the /etc/environment file to set system-wide Linux environment variables. The <NAME>='<VALUE>' pair should be added to the end of the file rather than export commands.

In Linux, how can I make a temporary environment variable?

The export command can be used to set a Linux environmental variable temporarily. Create an executable file for sample_script and run it from the command prompt. Only the current session's value of a temporary variable is available. Log out as the current user and then log back in to test it.

How is an environment variable removed?

You must use the unset command and the variable name to delete the environment variable. This command will permanently delete the variable.

Conclusion

In this blog, we had a detailed look at the Linux Environment, environment variables, their meanings, and commands to work efficiently with the Linux Environment variables. We hope that this article has provided you with the help to enhance your knowledge regarding the Linux Environment and if you want to learn more, do check out our Linux-related articles on-

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