cron params

[b_r_h]

Hello,

I have used cron over 10 years, but now I first time saw user-id on parameter. I tried to google it, but there was no success. Can somebody explain me?

This is on root's crontab

30 * * * * root /usr/sbin/ntpd -q -u ntp:ntp

*/usr/sbin/ntpd will run on every 30min as user ntp:ntp

What does this root means?

[lomcevak]

From the 'man 5 crontab'

The format of a cron command is very much the V7 standard, with a number of upward-compatible extensions.
Each line has five time and date fields, followed by a user name if this is the system crontab file, fol-
lowed by a command.

The system crontab is /etc/crontab. The 'root' in your example means to run the command that follows as user root.

[b_r_h]

That is what I suppose it to be. I forgot to look at man.

Thanks!