crontab: question about a special case of the dash character in the time field spec

Question

In the SuSE /etc/crontab the entry to run the cron.{hourly,daily,monthly,weekly} scripts is coded as:

-*/15 * * * * root test -x /usr/lib/cron/run-crons && /usr/lib/cron/run-crons >/dev/null 2>&1

Notice that the very first character of the specification is a dash character (-), and this is NOT a typo.

Can somebody explain what the time spec '-*/15' means?

BTW, the stuff seems to be running fine.

Thanks

Answer 1

It says the following in the man page for the crontab file (man 5 crontab):

If the uid of the owner is 0 (root), he can put a "-" as first character of a crontab entry. This will prevent cron from writing a syslog message about this command getting executed.