When you change something in Apache you need to reload or restart apache. Does anything need to be refreshed or restarted in Ubuntu Server 8.04 after I add/update the crontab? Thanks a bunch for your help.
3 Answers
No. As long as you use the crontab -e
command to edit the file, when you save it, you'll get a 'New Crontab Installed' message. That's it.
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1The same applies to
crontab <filename>
-- and tocrontab -r
, for that matter. Commented Jan 17, 2012 at 8:16 -
5But what if you did not use
crontab -e
to edit the file? Commented May 4, 2017 at 20:51 -
It should still work if you edited the file directly, assuming you had permissions to do so. It's still recommended to use the crontab command.– SafadoCommented May 5, 2017 at 17:01
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@user5359531 If you want to restart cron for whatever reason (which will force reloading of crontab files) see this SO question: stackoverflow.com/questions/10193788/…– JoLoCoCommented Jun 11, 2017 at 16:27
The usual thing is to use crontab -e
to edit the tables. The changes will be applied when you exit the editor. Otherwise the rules for re-reading changed crontabs are in the cron(8)
man page. They will be re-read eventually, you don't need to do anything.
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The change is not applied when you only save the file. Commented Mar 16, 2023 at 23:27
It's important that you elaborate on HOW/WHERE you are adding crons. But I think the following addresses any situation.
Yes, cron
needs to be made aware that you made changes, but no, you don't necessarily need to explicitly do anything to update it.
I'm paraphrasing the cron
manual here for the short version:
As mentioned, crontab -e
, the preferred method, will notify cron
that something changed.
However, cron
"wakes up" every minute to see if it has tasks for that minute. It also scans /var/spool/cron/crontabs
and will reload any files with an updated 'mtime' (modified time, meaning the file contents must have been updated).
So theoretically, if you do nothing, cron
will "wake up" and see you made changes to anything directly in /var/spool/cron/crontabs
.
But if you can, use crontab -e
. When you are done editing, it even gives you feedback that it was updated, it says:
crontab: installing new crontab
Specifically, this means that it refreshed its copy in memory for the file you just edited via crontab
.
Here's a quote from the manual CRON(8) :
cron searches its spool area (/var/spool/cron/crontabs) for
crontab files (which are named after accounts in /etc/passwd);
crontabs found are loaded into memory. Note that crontabs in this
directory should not be accessed directly - the crontab command
should be used to access and update them.