On RHEL 5.2, if I run 'crontab -e' and use this for my crontab file: MAILTO= # update rawhide trees daily at 6:00 AM HST 0 6 * * * /home/released/sync I get this error when crontab tries to install the new crontab file: [root@tenon released]# crontab -e crontab: installing new crontab "/tmp/crontab.XXXXIhC21M":1: bad minute errors in crontab file, can't install. Do you want to retry the same edit? But I use this for the crontab file: MAILTO="" # update rawhide trees daily at 6:00 AM HST 0 6 * * * /home/released/sync crontab is happy. I know the manpage says to either define MAILTO to something or use MAILTO="", but on other Unix systems (such as Solaris), you can set MAILTO= and it has the same effect. I wouldn't consider this a huge bug, just a user experience issue. This is the kind of thing that would likely end up on a Solaris admin's blog under something titled "why I hate RHEL..." because he spent a good portion of his day trying to figure out why crontab was choking. Well, that's just a theory anyway.
All cronjobs are checked for invalid syntax and warning is printed into logs since cronie (replacement for vixie-cron). I suppose this could also fix your issue, because you have been warned ;-)