OPEN device FOR purpose AS #handle {LEN = n}

The OPEN command opens communication with a device, which can be a disk file, a window, or a serial communications port. The command must be told what to open, for what purpose, and a descriptive, unique name or "handle" must be assigned to it so that other functions can access the open device. Handles must always begin with "#" to identify them as such and to distinguish them from other variables.

Note:  Any device that is opened during the normal operation of the program must be closed before program execution is finished.  See CLOSE 