Running program every 2 minutes with crontab

Question

What does

2 * * * *

means in crontab context?

I want to run my program every 2 minutes; is that what 2 * * * * means?

Answer 1

Not quite; that means every 2nd minute of the hour (i.e., 6:02, 7:02, 8:02, etc.). To make it every 2 minutes, use */2 in the first entry:

*/2 * * * * my-script.sh

You can read more about the crontab syntax and available options here at Wikipedia. Ubuntu's got a good overview too.