When you issue the run command to execute a program in the commands-only mode of MP Prism, the program starts up in the background. If the program needs to read terminal input, you must then issue the fg command at the (prism) prompt to run the program in the foreground. You cannot execute Prism commands while the program is executing in the foreground. To have the program run in the background and regain the (prism) prompt, type Control-z.