Int 2E  U - DOS 2+ - Pass Command To Command Interpreter For Execution     [l]

   DS:SI -> commandline to execute (see below)

Return: all registers except CS: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 commandline:
Offset Size    Description
 00h   BYTE    length of command string, not counting trailing CR
 01h   var command string
  N    BYTE    0Dh (CR)