Cron - schedule job every 30 minutes, starts half past full hour

Can I schedul开发者_运维百科e job in cron format so that it runs every 30 minutes from 6:30 am to 11:30, every day? How?

I think you will need 2 lines to achieve what you need:

30 6-11 * * * /path/to/your/command
0 7-11 * * * /path/to/your/command

In addition to Alvin's answer I would suggest to insert this line into your crontab:

*/30 6-11 * * * /path/to/your/command