I'm a newbie to Linux, and an intermediate on Unix with substantial experience in Unix Korn shell-scripting, etc. How different is Linux from a developer's perspective? I would not be doing any kernel programming. Are most of the basic commands identical (cut, troff, xargs, etc)? What about Linux is most different from Unix?
Well, first you'd have to define what you meant by "UNIX" specifically. SCO would tell you that only their product can really be called "UNIX," for example -- but I doubt that's what you mean! Linux is a very mainstream UNIX-alike If you've got some experience on Solaris, for example, you'll feel right at home. The Korn shell isn't the standard login shell (GNU bash is) but it's available. All of the programs you mention (cut, troff, xargs) are there, and work in the standard way.