5 Asterisks in crontab entry

Question

If there is an entry in crontab with the following syntax:

* * * * * /usr/bin/program

How often would this be run? How would it initially get launched?

Also see http://serverfault.com/q/79537/9278 – John Gardeniers Oct 01 '10 at 01:39 — John Gardeniers, Oct 01 '10 at 01:39

score 5 · Accepted Answer · answered Oct 01 '10 at 01:09

5

Your cron entry will execute every single minute of every hour of every single day of every single month of every single year

answered Oct 01 '10 at 01:09

Mark Henderson

score -1 · Answer 2 · answered Oct 01 '10 at 01:14

-1

A search for crontab syntax will give you man indepth explanations.

I find it handy to note the ordering in a comment at the top as a reminder.

answered Oct 01 '10 at 01:14

Or you can just do `man 5 crontab`. – Dennis Williamson Oct 01 '10 at 01:31
@Dennis, do you really think most of us would remember what number to use in a man command? If we could remember that much we probably wouldn't need to keep using man. – John Gardeniers Oct 01 '10 at 01:41
@John: `man crontab`, scroll to the bottom, see See Also "crontab(5)", `man man` the sections are listed on the second (25-line) screenful. "5 File formats and conventions". My comment was not intended as an "oh should already know this", but as "here's some useful information". – Dennis Williamson Oct 01 '10 at 01:46
1

@Dennis, I've never noticed that in a man file, probably because I only look for specific information. I'll try to keep it in mind. Thanks. – John Gardeniers Oct 01 '10 at 02:00
Just `man crontab` will do. The crontab manpage is not always in section 5. I'm typing this from Slackware Linux 13.1 and it's in section 1 here. – halp Oct 01 '10 at 04:55

2 Answers2