The DIR command has many switches (type DIR /?):
set DIRCMD=/b /o:-n
causes DIR to always use the /b and /o:-n switches. You can override these defaults for a given invocation of DIR:
DIR \[drive:\]\[path\] /-b
will perform the above dir without the /b switch but will still use the /o:-n switch.
You should set the DIRCMD environment variable in Control Panel / System / Environment.