Optimizing code via compiler flags
a collection of Unix/Linux/BSD commands and tasks
Felix von Leitner's original paper on BSD and Linux io performance.
The Linux Hater's Blog. Great fun, "in a way that xkcd is funny to Unixers. Whoever is writing that blog has extensive experience on Linux and enviable writing skills." --Miguel de Icaza
web-based source code browser for current and historic unix versions