So what does it do ? NewWait4Port is a replacement of the WaitForPort command provided with Amiga-OS. It waits for a Message Port to appear and then end itself. This is useful for batch scripts. Here's an example: run <>NIL: Miami:Miami ;start Miami TCP/IP-Stack as background task NewWait4Port MIAMI.1 ;wait for its Msg port to appear rx "ADDRESS MIAMI.1 ONLINE" ;send a rexx command to this port This script waits till Miami has been started and its ARexx Port is available. Then it tells Miami to go online. Without NewWait4Port you would try to send a rexx message before the Port is available as it needs some time for Miami to start. Of course you could use a simple wait 5. But you never really know how long Miami will need to start.