I am an old SunOS fossil who still puts /usr/ucb in my $PATH before /bin and /usr/bin. I am in the process of learning linux. It is just enough like what I know to lull me into a false sense of security, until I run into various interesting brick walls. For instance, under SunOS or Solaris you could pick up /usr/local/src, move it to /opt/src (or /home/src, if you prefer), and then ln -s /opt/src /usr/local/src, and be happy. Do that under linux and everything will look happy until you try to compile something, upon which zillions of ../../../blah.h includes will scurry out of the underbrush and reduce an entire tucows.c to a skeleton-make error faster than you can say "TECO". I used to think that "deep hardware spookery" was changing driver.c parameters before a kernel compile, or judicious use of clri on a truly recalcitrant filesystem. Never would I have guessed that commands like setpci, isapnp, and their ilk would come to be. In my glory days, it was only necessary to pull a gleaming bullet from man -k inode to shoot yourself in the foot. Linux provides an entire armory, stocked like a Niven/Pournelle wetdream with everything from casing molds and reloaders (/etc/conf.modules) to ravening molecular depolymerizer beams (isapnp.conf). Many, if not most, come thoughtfully pre-aimed somewhere above the knee. How marvelous, to live in such interesting times!