How to setup a SUDO_ASKPASS environment variable?

Question

What does setting up a SUDO_ASKPASS environment variable mean? How do you do it? Where do I declare it?

I am trying to use a shell script to shutoff my computer after a couple of minutes and initiate this script with java.

Answer 1

So I am not sure I'd use $SUDO_ASKPASS for this. Basically the value of $SUDO_ASKPASS is to be an executable that will spit your password to standard out when invoked. So, if your password was 'foo', you could write a shell script as:

#!/bin/bash
echo 'foo'

and place it in ~/bin/pw.sh. Then you would set the environment variable and execute the command as so:

SUDO_ASKPASS=${HOME}/bin/pw.sh sudo shutdown -h now

that example assumes that you're on Darwin; shutdown behaves differently on different operating systems.

A more intelligent way of doing this (and more secure) is to use the NOPASSWD argument in /etc/sudoers. We would add a line like this:

jane ALL=NOPASSWD: /sbin/shutdown

This again assumes you're on a Mac. And that your name is Jane. Change that. This way sudo will not ask for a password when you issue the command /sbin/shutdown. The command to (properly) edit sudoers is visudo.