INT 2E U - DOS 2+ - PASS COMMAND TO COMMAND INTERPRETER FOR EXECUTION           
	DS:SI -> commandline to execute (see #02585)
Return: all registers except CS:IP(Internet Protocol) The lower level (transport layer) of the TCP/IP protocol suite.	See also TCP, TCP/IP. destroyed
	AX = status (4DOS v4.0)
	   0000h successful
	   FFFFh error before processing command (not enough memory, etc)
	   other error number returned by command
Notes:	this call allows execution of arbitrary commands (including COMMAND.COM
	  internal commands) without loading another copy of COMMAND.COM
	if COMMAND.COM is the user's command interpreter, the primary copy
	  executes the command; this allows the master environment to be
	  modified by issuing a "SET" command, but changes in the master
	  environment will not become effective until all programs descended
	  from the primary COMMAND.COM terminate
	since COMMAND.COM processes the string as if typed from the keyboard,
	  the transient portion needs to be present, and the calling program
	  must ensure that sufficient memory to load the transient portion can
	  be allocated by DOS if necessary
	results are unpredictable if invoked by a program run from a batch file
	  because this call is not reentrant and COMMAND.COM uses the same
	  internal variables when processing a batch file
	hooked but ignored by 4DOS v3.0 COMMAND.COM replacement unless SHELL2E
	  has been loaded
	the MS-DOS 5 Programmer's Reference calls this "Reload Transient"


Format of DOS commandline:
Offset	Size	Description	(Table 02585)
 00h	BYTE	length of command string, not counting trailing CR
 01h	var	command string
  N	BYTE	0Dh (CR)