I cannot imagine how I would get my work done without Mac OS and Unix. Up to now I've been using Tenon's MachTen , a Unix program that runs as a Mac OS application, to enable me to have both on the same platform. With it, I can run Mac applications yet have a full-fledged Unix at my command. Now I can get the whole package from Apple - I picked up and installed a copy of OS X, Apple's new operating system, yesterday. Because OS X is installed with OS 9.1, the current Mac operating system, just about all current Mac applications can run in OS 9.1 mode.
Some new applications can run in native OS X mode and benefit from the new user interface.
But if all you got with OS X was the revised user interface it would not be that interesting or relevant to most readers of this column. Apple does not make this obvious in its documentation but Unix is there and can be used via a command line interface just like any other Unix versions. I have not been able to discover that any BSD 4.4 application is missing, and many gnu applications are included. So far I can find that only one of the Unix applications I depend on was not included and that is ssh. But the sources for ssh can be downloaded and compiled following these instructions .