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Does the cron which comes with OS X log its actions anywhere?

I'm not looking for output of any particular cron job, but rather log of what cron is doing. On a couple linux machines I've checked, there's /var/log/cron which has contents like:

Apr 26 11:00:01 localhost crond[27755]: (root) CMD (/root/bin/mysql-backup)
Apr 26 11:01:01 localhost crond[27892]: (root) CMD (run-parts /etc/cron.hourly)
Apr 26 11:07:01 localhost crond[28138]: (root) CMD (/usr/local/bin/python /home/
Apr 26 11:18:18 localhost crontab[28921]: (user2) LIST (user2)
Apr 26 11:18:22 localhost crontab[28929]: (user2) BEGIN EDIT (user2)
Apr 26 11:18:59 localhost crontab[28929]: (user2) REPLACE (user2)

This shows when jobs ran, when users viewed or edited crontabs, etc. This stuff is nowhere that I've found on my Snow Leopard machine.

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3 Answers 3

Much easier to simply add the following to /etc/syslog.conf :

cron.*      /var/log/cron.log

Then restart syslog

sudo launchctl unload /System/Library/LaunchDaemons/com.apple.syslogd.plist
sudo launchctl load /System/Library/LaunchDaemons/com.apple.syslogd.plist

Tested and working on OSX 10.7.4

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Wow, much simpler. Have an upvote. I wonder if this would've worked on Snow Leopard. –  Doug Harris May 15 '13 at 13:50
Works on Mavericks –  Clustermagnet May 8 '14 at 14:43
up vote 11 down vote accepted

I figured it how to log my cron job activity without switching each one over to launchd jobs.

The cron man page mentions -x options which enables "writing of debugging information to standard output." A side effect of this is that these also write basic information to standard error. Data sent to standard error is written to /var/log/system.log.

This results in data like this being written to /var/log/system.log:

debug flags enabled: misc
[42073] cron started
log_it: (user1 42084) CMD (/root/bin/mysql-backup)
log_it: (user1 42094) CMD (run-parts /etc/cron.hourly)

Since cron itself is launched by launchd, to enable this, I had to edit /System/Library/LaunchDaemons/com.vix.cron.plist so that it now looks like:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN"
<plist version="1.0">

I used -x misc here, but it didn't seem to matter which options I used. Adding the -x started the logging of job activity. I also added the StandardErrorPath to write to /var/log/cron.log instead of the default /var/log/system.log.

And then unload and reload this:

$ sudo launchctl
launchd% unload /System/Library/LaunchDaemons/com.vix.cron.plist 
launchd% load /System/Library/LaunchDaemons/com.vix.cron.plist 
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OSX now tends to use launchd rather than cron - Apple dev doc - so it might be there is nothing in cron to log.

Use launchctl to control the logging level of launchd. Som log info appears in system.log but more in the console app -> All messages

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Hmmm, switching to launchd is something I could consider, but I'm a grumpy old unix user. I followed that link. The example on that page is 1046 bytes long to replace 24 characters of crontab 0 0 7 11 0 happybirthday. –  Doug Harris Apr 26 '10 at 18:49

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