How to make environment variables persistent?

To make environment variables persistent across shell sessions in Linux, you need to define them in a shell configuration file. Here’s how to do it:

For Bash Users:

1. Open the .bashrc or .bash_profile file:
   You can use a text editor like nano or vim. For example:

   nano ~/.bashrc

   or

   nano ~/.bash_profile

2. Add the Environment Variable:
   At the end of the file, add a line to export your variable. For example:

   export MY_VARIABLE="my_value"

3. Save and Exit:
   If you are using nano, press CTRL + X, then Y, and Enter to save and exit.

4. Apply the Changes:
   To apply the changes without restarting the terminal, run:

   source ~/.bashrc

   or

   source ~/.bash_profile

For Zsh Users:

1. Open the .zshrc file:

   nano ~/.zshrc

2. Add the Environment Variable:
   Add the export line as shown above:

   export MY_VARIABLE="my_value"

3. Save and Exit:
   Save the changes as described earlier.

4. Apply the Changes:
   Run:

   source ~/.zshrc

Verification:

To verify that the environment variable is persistent, you can open a new terminal session and run:

echo $MY_VARIABLE

If it outputs the value you set, the variable is now persistent across sessions.