I am running CentOS 5.3 and have just the two accounts "root" and "buz". I would like to be able to issue "shutdown" from the account "buz", and thus created /etc/shutdown.allow with the single entry "buz" (without any quotes). I still get the error message "only root can do this" (or something similar) even if I include the '-a' option on the shutdown command. What am I missing ?