I'm working on a method to get immediate printing to a receipt printer (dot matrix) for point-of-sale app.

I'm using SET ALTERNATE TO filename.txt and then issuing several ?? and ? lines. Then a SET ALTERNATE OFF and a CLOSE ALTERNATE. To print the file, COPY filename.txt TO prn.txt (printer on LPT1 or prn)

I'm getting an error "there is not enough disk space for C:\...\prn.txt." The cause is this character, "  ", at the end of the alternate file. If I erase this character, there is no problem.

Any suggestions on how to prevent this character in the alternate file or any other work around?