env Command in Linux

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env is a Linux command that is used to display or modify environment variables of the current shell session. The environment variables on the other hand are dynamic values that can affect the behavior of the processes running on your system.

By executing the env command without an argument, you will be able to view the list of all current environment variables on your system. Apart from that, you can also use the env command to run a command with a modified environment, without changing the current one. This practice is pretty much useful in scripts to ensure the correct interpreter is used.

Table of Contents

Here is a comprehensive guide to the options available with the env command −

• Syntax of env Command
• env Command Options
• Examples of env Command in Linux

Syntax of env Command

The env command in Linux is a handy tool for managing environment variables. Here’s a simple breakdown of its syntax −

env [options] [NAME=value]... [command [args]...]

Here,

• [options] are flags used to change the command’s behavior.
• [NAME=value] is the set environment variables for the command.
• [command [args]...] is the command to run with the specified environment.

env Command Options

With env command on Linux, you can use different options, these are discussed in the table provided below −

Examples of env Command in Linux

Let’s explore a few examples of env command in Linux, which are as follows −

• View All Environment Variables
• Run a Command with a Modified Environment
• Ignore the Current Environment
• Unset an Environment Variable
• Change the Working Directory

View All Environment Variables

You can use the env command on Linux without an argument to display all current environment variables, as given below −

env

The above command will list all the environment variables set in your current session −

Run a Command with a Modified Environment

You can also run a command with a specific environment variable set by using the env command followed by the variable and the command. For example, to run a script with a custom variable, you can consider the following command −

env MY_VAR=hello ./script.sh

Note − You may use sudo with the env command in some cases if you are login to your Linux system as a non root user.

Ignore the Current Environment

If you want to run a command with an empty environment, ignoring all existing variables, you can use the -i option with the env command. This is useful for testing how a command behaves without any environment variables, for example −

env -i command

Unset an Environment Variable

You can also remove a specific environment variable before running a command by using the -u option with the env command followed by the variable name. For example, to unset the PATH variable, you can use the below-given command −

env -u PATH ./script.sh

Change the Working Directory

If you want to change the working directory before running a command, you can simply use the -C option with the env command and the directory path in the end. This runs the command in the specified directory −

env -C /new/directory command

In this way, you can use the env command on your Linux system.

Conclusion

The env command is a powerful tool used in Linux for managing environment variables. By using the env command, you can view all current environment variables, or run commands with a modified environment without altering the existing one.

In this tutorial, we explained the env command, its basic syntax, followed by different options that you can use with the command. Further, examples are explored in the end to help users understand the env command usage. This will help enhance their ability to manage and troubleshoot environment settings in an effective manner.