Tandy 1000 Basic Reference Manual page 309

Chapter 10 I BASIC Keywords
Examples
S H E L L
transfers control to COMMAND.COM. You can execute MS-DOS
commands such as:
D I R
T I N E
and then type EXIT to return to BASIC.
The following command uses redirection of input and output and
the MS-DOS SORT command.
S H E L L " S 0 R T < d a t a . i n > d a t a . o u t "
sorts the text from data.in and writes it to data.out.
307