The reason that I want to be able to run it from the command line and that it needs to be small and free is so that I can use it with my installers. If you can use it from a bat file, I can rip from an NSIS script. Since it would have to be distributed with the installer, I need to be able to do so legally and it needs to be relatively small, without being installed. I had already looked at ImgBurn, but it seems to need to be installed and the executable is 2.23 MB. I would like to keep it under a MB in size.
I was able to use mkisofs, part of the CDR Tools, with my Lighthouse installer to create ISOs of the discs, since I was unable to concatenate the discs the way I was able to with most of the other multi-disc Sierra games. But as I said, cdda2wav does not seem to work reliably across different PCs.
I guess I'll take a close look at ImgBurn to see if I can use the executable without being installed. If it works, I'll need to see if I can distribute it packed in my installer.