When scheduling a monitor, besides picking one of the simple alternatives testRTC offers “out of the box”, you can express your own monitor’s frequency by using a cron expression.
A cron expression is a string consisting of six or seven subexpressions (fields) that describe individual details of the schedule.
These fields, separated by white space, can contain any of the allowed values with various combinations of the allowed characters for that field.
Cron syntax:
┌───────────── min (0 - 59) │ ┌────────────── hour (0 - 23) │ │ ┌─────────────── day of month (1 - 31) │ │ │ ┌──────────────── month (1 - 12) │ │ │ │ ┌───────────────── day of week (0 - 6) (0 to 6 are Sunday to │ │ │ │ │ Saturday, or use names; 7 is also Sunday) │ │ │ │ │ │ │ │ │ │ * * * * * command to execute
Examples:
*/30 * * * * Every 30 minutes 1 0 * * * Every day, at 00:01 AM 0 * * * * Every hour */5 * * * * Every 30 minutes
Online generator
You can use an online cron expression descriptor to create these expressions in a way that is more human readable. We recommend using this Cron Expression Generator. Take into account the following:
- Time is adjusted to UTC on our service
- Remove the 1st 0 as we don’t use seconds
- Remove the last * as we don’t use years