$3

// create with Date
var job = crontab.create('ls -lh', new Date(1400373907766));

// create with comment
var job = crontab.create('ls -lt', null, 'comment 2');

// create special: @reboot, @hourly, @daily, @weekly, @monthly, @yearly, @annually, @midnight
var job = crontab.create('ls -la', '@reboot');

// check valid
var job = crontab.create();
if (job == null) {
console.log('failed to create job');
}

// remove object
var job = crontab.create('ls -lr', '0 7 1,2,3,4,5', 'comment 3');
crontab.remove(job);

// remove conditions
crontab.remove({command:'ls -lh', comment:/comment 2/});

// manipulate: every business hour
var job = crontab.create('ls -l');
job.minute().at(0);
job.hour().between(8, 17);
job.dow().between('mon', 'fri');

// manipulate: every other hour on weekday nights
var job = crontab.create('ls -l');
job.hour().between(19, 0).every(2);
job.hour().between(0, 6).every(2);
job.dow().between('mon', 'fri');

// manipulate: summer
var job = crontab.create('ls -l');
job.month().between('jun', 'sep');

// manipulate: Christmas
var job = crontab.create('ls -l');
job.minute().at(30);
job.hour().at(9);
job.dom().on(24);
job.month().in('dec');

// show all jobs
var jobs = crontab.jobs();

// show jobs with conditions
var jobs = crontab.jobs({command:'ls -l', comment:/comment 1/});

// reset jobs to their original state
crontab.reset();

// save
crontab.save(function(err, crontab) {

});

// create with a pair of arguments
crontab.vars().add('FOO', 'foo');
// create multiple with an object argument
crontab.vars().add({'FOO':'foo', 'BAR':'1'});

// remove all env variables
crontab.vars().rm();
// remove selected env variables
crontab.vars({name: 'FOO'}).rm();

// save
crontab.save(function(err, crontab) {

var command = 'ls -l';

crontab.remove({command:command});
crontab.create(command, '@reboot');

crontab.save(function(err, crontab) {

var uuid = '64d967a0-120b-11e0-ac64-0800200c9a66';
var nodePath = process.execPath.split('/').slice(0, -1).join('/');
var exportCommand = 'export PATH=' + nodePath + ':$PATH';
var foreverCommand = require('path').join(__dirname, 'node_modules', 'forever', 'bin', 'forever');
var sysCommand = exportCommand + ' && ' + foreverCommand + ' start ' + __filename;

crontab.remove({comment:uuid});
crontab.create(sysCommand, '@reboot', uuid);