For this purpose, it really doesn't matter which unix you use, much less which Linux distribution -- all 'unixes' are close enough to the ur-unix that your K&R knowledge, and that gleaned from The Unix Programming Environment, will be equally applicable to all of them. If I recall correctly, the latter book is fairly SysV-ish, but notes the BSD behaviour when it differs (or maybe it's the other way around). After all, K&R was originally written on a substantially older version of Unix than any that are in current use.
The differences between unixes tend to be a pain, but when you get to the point where this matters, you're arguably no longer a beginner, and can read a man page for yourself (man pages trump any book).
For information, Linux largely splits the difference between the two major unix lineages in those cases where they differ -- SysV and BSD: more often than not it looks SysV-ish, but frequently implements both APIs where there's a difference.
If you're interested in being portable, then you still don't want to focus on a particular unix, but instead learn to love autoconf, port-early-and-often, and bookmark the POSIX spec.