Syntax:

shutdown minutes [restart] shutdown now [restart] shutdown stop

This command shuts down the server. It can only be used by privileged users.

If the first argument is a number the server shuts down in that number of minutes. If the first argument is the word now the server shuts down immediately. If the word stop is given as the first argument the shutdown sequence is halted.

You can use the optional argument restart to restart the server immediately after the shutdown. This is useful for installing a new version of the server. During the last 10 minutes of a shutdown sequence the server disables all new logins.