$ cat ~/.mtoolsrc
MTOOLS_TWENTY_FOUR_HOUR_CLOCK=1
MTOOLS_DATE_STRING="yyyy-mm-dd"
drive a:
  file="~/diskette.img" mformat_only 1.44m
$ dd if=/dev/zero of=~/diskette.img bs=1024 count=1440
1440+0 records in
1440+0 records out
1474560 bytes (1.5 MB, 1.4 MiB) copied, 0.00667722 s, 221 MB/s
$ mformat a:
$ mdir
 Volume in drive A has no label
 Volume Serial Number is 1168-805E
Directory for A:/

No files
                          1 457 664 bytes free

$ for num in 1 2 3; do echo -ne "$num\r\n" | mcopy - "a:file$num"; done
$ mdir
 Volume in drive A has no label
 Volume Serial Number is 1168-805E
Directory for A:/

file1                3 2020-11-03  15:52
file2                3 2020-11-03  15:52
file3                3 2020-11-03  15:52
        3 files                   9 bytes
                          1 456 128 bytes free

$ mtype a:file1 a:file2 a:file3 >unixfile
Several file names given, but last argument (-) not a directory
$ mtype a:file1 a:file2 a:file3 | mcopy - a:msdosfile
Several file names given, but last argument (-) not a directory
$ mtype a:msdosfile
1
2
3
$ cat unixfile
1
2
3
$