Gruntfile to trigger new Vagrant 1.5 rsync command when catching changes. Faster than Vagrant rsync-auto bundled command, mainly because Grunt only watches specified paths while Guard/Listen (used internally by Vagrant) watches the whole (sub)-folders.

rsync-auto grunt alternative.coffee

terminal = require('color-terminal')

log = (error, stdout, stderr, cb) ->
    if error
        terminal.color('red').write stdout
    else
        terminal.color('green').write stdout

    cb()
    
module.exports = (grunt) ->
    grunt.loadNpmTasks 'grunt-contrib-watch' # https://github.com/gruntjs/grunt-contrib-watch
    grunt.loadNpmTasks 'grunt-shell' # https://github.com/sindresorhus/grunt-shell

    grunt.initConfig
        vagrantPath: '<path to .vagrant dir>' # TO MODIFY

        watch:
            src:
                options:
                    spawn: false
                files: [
                    'some paths...' # TO MODIFY
                ]
                tasks: 'shell:vagrant_rsync'

        shell:
            vagrant_rsync:
                options:
                    callback: log
                command: 'cd <%= vagranPath %> && vagrant rsync' # --debug to get full logs