Nice. However, I feel there're two things really needed to be done here: move all that cat|du|... to some src|source|whatever directory and add 'tests' directory with somewhat more robust tests layout than the current one. It would be really cool to replace (seriously, just for the arts sake) coreutils with this one, but I wouldn't dare to do it if I'm unable to easily verify that they both work and work at least almost as fast as coreutils on my platform. It's important stuff, you know, otherwise it wouldn't be called "coreutils", really…
