An environment variable is a dynamic object that defines a location to store some value. We can change the behavior of the system and software using an environment variable. Environment variables are very important in computer programming. They help developers to write flexible programs.

There are Different ways to List Environment Variables in Linux. We can use the env, printenv, declare, or set command to list all variables in the system. In this Post , we’ll explain how to use Different ways to List Environment Variables in Linux.

You can also learn how to A Step-by-Step Guide to Set Environment Variables in Linux

Using printenv Command

The printenv command displays all or specified environment variables. To list all environment variables, simply type:

We can specify one or more variable names on the command line to print only those specific variables. Or, if we run the command without arguments, it will display all environment variables of the current shell.

For example, we can use the printenv command followed by HOME to display the value of the HOME environment variable:

In addition, we can specify multiple environment variables with the printenv command to display the values of all the specified environment variables:

Let’s display the values of the HOME and SHELL environment variables:

Using env Command

The env command is similar to printenv but is primarily used to run a command in a modified environment. env is another shell command we can use to print a list of environment variables and their values. Similarly, we can use the env command to launch the correct interpreter in shell scripts.

We can run the env command without any arguments to display a list of all environment variables:

 Using set Command

The set command lists all shell variables, including environment variables and shell functions. It displays more than just environment variables, so the output will be more comprehensive:

set is yet another command-line utility for listing the names and values of each shell variable. Although the set command has other uses, we can display the names and values of all shell variables in the current shell simply by running it without any options or arguments:

Using export -p Command

The export -p command shows all environment variables that are exported to the current shell session:

Using the declare Command

declare is another built-in command used to declare a shell variable and display its values. For example, let’s run the declare command without any option to print a list of all shell variables in the system: The declare -x command lists environment variables along with some additional information, similar to export -p:

Using the echo Command

echo is also used to display values of the shell variable in Linux. For example, let’s run the echo command to display the value of the $HOSTNAME variable:

Conclusion

There are multiple ways to list and manage environment variables in Linux, ranging from command-line utilities to graphical tools. Each method provides a different level of detail and flexibility, allowing users to choose the one that best fits their needs.

Incorporating these methods into your blog post will provide a comprehensive guide for readers looking to understand and manage environment variables in Linux.

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