Cron every 30 seconds?

Question

Task Schedulers

In general, I have such a question, who really knows the hosting that has cron? So that you can run one file every 30 seconds.
Or how to do so? To have the file run every 30 seconds.

Answer 1

Cron is at least a minute.
Once every 30 seconds, this means running a script every minute that does something, then sleeps for 30 seconds and does it again.

Answer 2

* * * * * <your task>
* * * * * sleep 30 && <your task>