IFEXISTS @{" SYSTEM " link "system"} NAME|~NAME ElseIfExists, Else, EndIf AndIfExists, OrIfExists This command works exactly the same as the "IF" command, but with different arguments. Look at the if command to understand it. It lets you see if various things such as PORT, FILE, DEVICE etc.. exist in your system, or not. Example : TestVar = "MyWindow" IfExists WINDOW $TestVar Say "My Window is open." Else Say "My Window is closed" EndIf You can also use a negative form to check if something does *not* exist, by puting a ~ character in front of the item you're looking for : IfExists PORT ~AREXX ; Port AREXX doesn't exist run 'RexxMast' endif