Log of cron actions on OS X

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

from : http://superuser.com/questions/134864/log-of-cron-actions-on-os-x