CRON is a term came from UNIX/LINUX operating systems. That is a name of a daemon - a special resident program responsible for the process scheduling, i.e. it launches programs and commands on selected time.

CRON uses a special language for describing when a command should be launched. This is one of the most powerful languages designed for that purposes. It can describe almost any type of schedule which is possible to imagine.

Let's consider some common cases of its using. There are two ways how to create the task schedule.

The first one provides a simple interface. You can select the most common periods: every minute/hour/day/month/week or select the real time you want the task to start synchronization, replication or monitoring.

The second way is for users who are familiar with the CRON language. To enter it mark the Advanced check box. Now we are ready to discuss the main templates of the CRON using.

Here are some basics of the CRON language. The CRON command consists of 5 places divided by space. Every place can contain digits 0..9, *, +. Groups of digits can be separated by - and ",".

The table below shows the most common and useful samples of the templates:

Every midnight	0 * * * *
End of week midnight	0 0 6 * *
The end of a month	0 0 1 * *
The end of a year	0 0 1 1 *
Every work day noone	0 12 * * 1-5
Every 10,20,40 minutes of an hour	10,20,40 * * * *
Every begin of an hour from 8 to 17	0 8-17 * * *

As you could note the CRON language is enough easy but very powerful. It can describe intervals between one minute to year for starting the backup, replication or synchronization job.

We can advise you with your own interval creation. Contact us at our support center.