That appears to be a line from your /etc/sudoers file.
If the "#" were deleted from that line, it would mean that members of the group "users" [%users] on the local machine, not remotely [localhost] may operate the command to shut down the computer [/sbin/shutdown -h now].
The "#" means that that line is ignored by the program that reads it. It is treated as a comment.
Try looking at the manual for your sudoers file for a better idea.
"man sudoers" typed into a terminal.
Last edited by truthfatal; 02-27-2008 at 10:59 AM.