How to set env variable in Linux?

Setting Environment Variables in Linux

Introduction

Setting environment variables in Linux is a crucial step in customizing the system to suit your specific needs. Environment variables are used to store settings that can be accessed by various programs and services running on the system. In this article, we will explore the process of setting environment variables in Linux, including how to set them, how to use them, and some best practices to keep in mind.

Why Set Environment Variables?

Before we dive into the process of setting environment variables, let’s quickly discuss why they are important. Environment variables are used to store settings that can be accessed by various programs and services running on the system. For example, you might set an environment variable to specify the default text editor to use, or to set the default language for a particular application. By setting environment variables, you can customize the system to suit your specific needs and preferences.

Setting Environment Variables

To set an environment variable in Linux, you can use the export command. Here’s a step-by-step guide on how to set environment variables:

  • Step 1: Open a Terminal

    • Open a terminal on your Linux system. You can do this by searching for "Terminal" in your system’s application menu or by using the gnome-terminal or xfce4-terminal command.

  • Step 2: Navigate to the Directory Where You Want to Set the Variable

    • Once you’re in the terminal, navigate to the directory where you want to set the environment variable. You can do this by using the cd command.

  • Step 3: Set the Environment Variable

    • Use the export command to set the environment variable. For example, to set the PATH environment variable, you would use the following command:
      export PATH=$PATH:/usr/local/bin

  • Step 4: Verify the Variable

    • To verify that the environment variable has been set, you can use the echo command. For example:
      echo $PATH

  • Step 5: Use the Variable

    • Once you’ve set the environment variable, you can use it to access the variable in your programs and services. For example, if you set the PATH environment variable to /usr/local/bin, you can use the following command to access the ls command:
      ls

  • Best Practices

    • Use Environment Variables for System Settings: Environment variables are used to store system settings that can be accessed by various programs and services running on the system. Avoid using environment variables for user-specific settings, as they can be accessed by multiple users.
    • Use Environment Variables for Program Settings: Environment variables are used to store settings that can be accessed by specific programs and services. Use environment variables to customize the behavior of your programs and services.
    • Use Environment Variables for Configuration Files: Environment variables are used to store settings that can be accessed by configuration files. Use environment variables to customize the behavior of your configuration files.

Using Environment Variables in Scripts

Environment variables are also used in scripts to customize the behavior of the script. Here’s an example of how to use environment variables in a script:

  • Step 1: Open a New File

    • Open a new file in your preferred text editor.

  • Step 2: Add Environment Variables

    • Add the following lines to the file to set the PATH and HOME environment variables:
      export PATH=$PATH:/usr/local/bin
      export HOME=/home/user

  • Step 3: Save the File

    • Save the file with a .sh extension.

  • Step 4: Run the Script

    • To run the script, use the following command:
      ./script.sh

  • Step 5: Verify the Variable

    • To verify that the environment variables have been set, you can use the echo command. For example:
      echo $PATH

      echo $HOME

  • Best Practices

    • Use Environment Variables for System Settings: Environment variables are used to store system settings that can be accessed by various programs and services running on the system. Avoid using environment variables for user-specific settings, as they can be accessed by multiple users.
    • Use Environment Variables for Program Settings: Environment variables are used to store settings that can be accessed by specific programs and services. Use environment variables to customize the behavior of your programs and services.
    • Use Environment Variables for Configuration Files: Environment variables are used to store settings that can be accessed by configuration files. Use environment variables to customize the behavior of your configuration files.

Common Environment Variables

Here are some common environment variables that you should be aware of:

  • PATH: The path to the directory where the system searches for executable files.
  • HOME: The path to the user’s home directory.
  • USER: The name of the user.
  • GROUP: The name of the group.
  • SHELL: The shell that is used to execute commands.
  • TERM: The terminal type.

Conclusion

Setting environment variables in Linux is a crucial step in customizing the system to suit your specific needs. By following the steps outlined in this article, you can set environment variables, use them, and customize the behavior of your programs and services. Remember to use environment variables for system settings, program settings, and configuration files, and to follow best practices to keep in mind.

Additional Resources

  • Linux Documentation: The official Linux documentation is a great resource for learning about environment variables and other Linux commands.
  • Linux Tutorial: A Linux tutorial is a great resource for learning about Linux and environment variables.
  • Stack Overflow: Stack Overflow is a great resource for asking questions about environment variables and other Linux commands.

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