Use forever to run a grunt command

Gruntfile.js

module.exports = function (grunt) {
    // Project configuration.
    grunt.initConfig({
        pkg: grunt.file.readJSON('package.json'),
        watch: {
            scripts: {
                files: ['<The file(s) to watch'],
                tasks: ['<The task to run>'],
                options: {
                    spawn: false
                }
            }
        },
        forever: {
            watch: {
                options: {
                    index: 'gruntstart.js',
                    logFile: 'watch.logs',
                    outFile: 'watch.logs',
                    errFile: 'watch.logs'
                }
            }
        }
    });

    // Load modules
    grunt.loadNpmTasks('grunt-forever');
    grunt.loadNpmTasks('grunt-contrib-watch');
    
    // Register tasks
    grunt.registerTask('default', ['forever:watch:restart']);
};

gruntstart.js

/**
 * Credit to Антон Брагин
 * from http://stackoverflow.com/questions/15622116/grunt-js-watch-forever 
 * For providing this piece of code
 */
 
var exec = require('child_process').exec;

exec('grunt watch > log/grunt.log',
    function (error, stdout, stderr) {
        console.log('stdout: ' + stdout);
        console.log('stderr: ' + stderr);
        if (error !== null) {
           console.log('exec error: ' + error);
        }
});