crontab
in the late 1990s, and I still run many of those same crontabs. I mean, same program, same times. So, my understanding of that tool is very tied to that time. Of course, very little changes in technology over 15 years. </sarcasm> So I recently looked through
man 5 crontab
and found that there are special strings for certain common times. @reboot | Run once, at startup. |
---|---|
@yearly | Run once a year, "0 0 1 1 *". |
@annually | (same as @yearly) |
@monthly | Run once a month, "0 0 1 * *". |
@weekly | Run once a week, "0 0 * * 0". |
@daily | Run once a day, "0 0 * * *". |
@midnight | (same as @daily) |
@hourly | Run once an hour, "0 * * * *". |
Some of these come with variable utility. What are you doing on a system that's
@yearly
? Sending "Happy New Year!" to everybody you know? There's much here that strikes me as better done connecting to a calendar. In fact, I'm hatching an idea of setting up a calendar in Google Calendar to do that sort of wide-ranging crontabby or batchy stuff. If something runs less common than weekly, it doesn't get into my crontabs.Except...
I'm really drawn to the
@reboot
string. For my work setup, I have FUSE mounts to a great number of machines (which I really use) and a specific line to configure the line-in to go directly to line-out so I can route my Windows box and Android phone through my Linux box to my headphones. I've put those commands into my crontab at @reboot
.
One time @yearly might come in handy is in the case of license files. For example, the WXP weather analysis package has a license file that expires when the ball falls in Times Square. A crontab entry like
ReplyDelete@yearly cp /blah/wxp.lic-new /blah/wxp.lic
would be useful.
OK. That's an interesting case. Thanks for the comment, Ben.
ReplyDelete