OnCommand is a TIdRSHCommandEvent property that represents the event handler signalled when a RSH client connection needs to perform authentication and execution of a service request. 

OnCommand is triggered during execution of the context for the client connection, and uses arguments to the event handler to identify values needed during authentication and command execution. 

OnCommand is signalled after the optional connection for redirected standard error output has been created, bound, and successfully connected. In addition, null terminated values for the client user name, host user name, and the RSH command have been read from the request connection prior to triggering OnCommand. 

Applications must assign a procedure to the event handler to allow responding to the event notification. The event handler can be used to authenticate the client and host user name values, to execute the command, and to send error or result values using the optional connection for redirected standard error output.

TIdRSHCommandEvent TIdRemoteCMDServer.SendError TIdRemoteCMDServer.SendResults