# Environment Variables

You can run `printenv` or `env` in your terminal

1)How to set Environment variables:-

`myVAR=hello`

`printenv myVAR=hello` OR `echo $myVAR`

2)How to unset it?

`unset myVAR` then `echo $myVAR`

3)If you type export `myVAR=hello` then you can do `echo $myVAR`

You can add this line in user profile. The tilde symbol (~) represents the home directory.

a)~/.bash\_profile (CentOS)

b)~/.bash (Ubuntu)

Add this line in any one of the file

`export myVAR=hello`

You can echo in new terminal but you won’t be able to echo in your current shell

To solve this, type `source ~/.profile` then it will show the output in your current shell.

But if you open in new tab in your current shell, then it won’t show the output.

Then add this line `export myVAR=hello` in ~/.bashrc