Cron jobs and random times, within given hours

Question

I need the ability to run a PHP script 20 times a day at completely random times. I also want it to run only between 9am - 11pm.

I\'m familiar with creating cron job

Answer 1

My first thought would be to create one cron job launching 20 randomly scheduled at jobs. The at utility (http://unixhelp.ed.ac.uk/CGI/man-cgi?at) is used for executing commands at specified time.