INT 2E - Execute Command Using Base Level Command Interpreter

(Undocumented DOS 2.0+)

	DS:SI = pointer to command string to be executed

	returns nothing ???

	- causes the base level COMMAND.COM to execute a command as if it
	  were typed from the keyboard
	- the transient portion of COMMAND.COM must be loaded if not resident
	- first byte of the string contains the string length, inclusive
	- command string must be terminated with a CR
	- all registers including SS & SP are destroyed;  SS & SP should be
	  preserved in your own code segment
	- can be used to modify parents environment with SET command
	- incompatible under some software multitasking systems
	- before returning to the parent program this interrupt will
	  attempt to execute the "current" batch file (if the parent or
	  any ancestors were invoked from a batch file.   This can cause
	  remaining lines in a batch file to execute before the parent
	  program finishes and fragment memory