Wrong pid returned in node executable

Working on a cli tool for my latest project. I'm writing a stop method and trying to kill the node process based on its pid.

This is the code I have but it looks like I'm only getting the pid for the grep function

#!/usr/bin/env node

(function () {
var args = process.argv.slice(2),
    exec = require('child_process').exec;

args.forEach(function (arg) {
    switch (arg) {
        case 'start':
            require('./library/Ubui');
            return;
        break;
        case 'stop':
            //I am aware this will kill the grep instance too
            //but I don't care. Why should we?
            exec('ps aux | grep ubui.js | cut -c11-15', function (a, b) {
                var ubuifs = b.split("\n");
                console.log(ubuifs);
                ubuifs.forEach(function (pid) {
                    if (pid !== '') {
                        console.log('\x1b[33mAttempting to kill process pid: ' + pid + '\x1b[0m');
                        exec('kill ' + pid, function (a, b) {
                            console.log(a, b);
                        });
                    }
                });
            });
        break;
    }
});
})();

If anyone has any idea you could answer here or do a pull request on the github here and explain why it isn't working? It would be a really handy cli tool if I could get this working!

Cheers