> On Jul 6, 2026, at 4:31 PM, Bret Johnson via Freedos-devel > <[email protected]> wrote: > > >> >> command.com >> >> IF EXIST Z:NUL echo drive Z: exists >> >> which is essential to test for loaded network/ram drives has been non >> functional fo ~15 years > > Just as a comment, I don't normally use FreeDOS but if this test doesn't work > it's a serious problem -- not just testing for the existence of drive letters. > > All the standard character devices in DOS (NUL, CON, COMx, LPTx, CLOCK$, > etc.) are supposed to act like there is a file by that name in EVERY > subdirectory on every disk there is. This means you can't (or at least > shouldn't be able to) create a file with any of those device names anywhere > and also allows input/output redirection using those devices from anywhere. > > I've never experimented with "non-standard" character devices (something > normally installed with a device driver in CONFIG.SYS) but suspect they would > (or at least should) work the same way.
About 3 years ago, I put together a test batch that demonstrated correct and incorrect results of “if exist” You can find information on those tests, the test batch and the results at that time on my server at https://fd.lod.bz/redist/testing/devNUL/ I have tested this in a while. So, the results could be very different with later kernels. :-) Jerome > > > _______________________________________________ > Freedos-devel mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/freedos-devel
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