I'm using ubuntu 12.04 and I want to execute a script every 5 hours . I setup cron with crontab -e and putted
* */5 * * * sh /home/cron_script.sh
The script is executed every minute.
The first * needs to be a 0 or whatever minute of the hour you want the script to run...eg 30 would mean script will run at 0030,0530, 1030, etc.