Int 2F Fn AE01  U - DOS 3.3+ Internal - Installable Command - Execute      [l]

   AX = AE01h
   DX = FFFFh
   CH = 00h
   CL = length of command name (4DOS v4.0)
   DS:SI -> command name buffer (see AX=AE00h)
   DS:BX -> command line buffer (see AX=AE00h)

Return: DS:SI buffer updated
     if length byte is nonzero, the following bytes contain the uppercase
     internal command to execute and the command line buffer contains the
     command's parameters (the first DS:[SI] bytes are ignored)

Notes: this call requests execution of the command which a previous call to
     AX=AE00h indicated was resident
   APPEND hooks this call