When you run sudo in Ubuntu, your administrative privileges last for 15 minutes by default so you don’t have to type in your password with every command. If that is too long or short for your tastes, you can change it with a simple tweak.
Run the following command in a Terminal:
Scroll down to the line that looks like this:
and change it to this:
Change 30 to the time, in minutes, that you want it to wait before it times out. You can also change it to 0 if you want a password prompt every time you run sudo, or -1 if you never want a password prompt (though we don’t recommend this).
Press Ctrl+X to finish editing, Y to save changes, and Enter to exit if you’re on Ubuntu. Other Linux distros may have different commands depending on the default editor.