Radio Shack TRS-80 Model II Reference Manual page 190

Model II
TRSDOS
DOSCMD
DOS Command (function code 37)
This routine sends TRSDOS a command. After the command is executed,
control returns to TRSDOS (TRSDOS READY). All Open files are closed
automatically.
Entry Conditions
(HL)
=
TRSDOS command string
B =
Length of command string
A
=
37
RETCMD
Return after Command (function code 38)
This routine sends TRSDOS an operator command. After completion of the
command, control returns to your program. All Open files are Closed
automatically.
Note: Take care thatTRSDOS doesn't overlay your program while loading the
command file you specified. Most TRSDOS library commands use memory
below
X'27FF';
a few go up to but not including
X'2FFF'.
Single-drive, single-
disk copies use all user memory. See Library Commands for details.
Entry Conditions
(HL)
=
TRSDOS command string
B
=
Length of command string.
A
=
38
Exit Conditions
NZ
=
Error
A
=
Error Code
226