FAILAT ErrorNumber When you use CLI (without run) and other commands, you get a "return code" ($$RETCODE) when whatever you did with this command finishes executing. This return code is stored in the internal variable $$RETCODE. If this return code is equal or more than the ErrorNumber you have set with the FAILAT command, then Gui4Cli will stop execution immediately, and return to the waiting for something to happen. The default value for ErrorNumber is 10, which most programs return if a pretty serious (but not fatal) error occurs. You can set this to 20 for example, if you do not want anything but a very serious error interrupting your CLI commands. (or 1000 for kamikaze pilots) You can also declare an event type xONFAIL (see "Other Events"), whose commands will be executed if such an error occurs. This command eliminates the need for constantly checking $$RETCODE to see if an error occurred, before proceeding to other commands. $$RETCODE is reset to 0, after such an error.