Also handy for your .zshrc or .bashrc: mkcd () { mkdir -p $1 cd $1 } Also, moving a tarball before unpacking it is indeed brain-damaged, but,

Also handy for your .zshrc or .bashrc: mkcd () { mkdir -p $1 cd $1 } Also, moving a tarball before unpacking it is indeed brain-damaged, but, cd /target/directory tar xzvf /source/dir/sourcefile.tar.gz works for me. I don't know why you would need -C, though it saves five keystrokes ("cd -") if you didn't want to end up in the target directory for some reason. Listing 6 looks like a bad idea; it either goes to or makes a directory, depending on whether it existed. I realize he's just illustrating the use of "||", but don't copy the command. Usually you would want pwd to be an invariant. It looks like he really wanted to write: [ -d tmp/a/b/c ] || mkdir -p tmp/a/b/c GNU mkdir -p will not complain if the target directory already existed, so you could just run mkdir -p tmp/a/b/c but then that doesn't illustrate the use of "||". Overuse of 'cat' is a hard habit to break for some reason, especially since it's so harmless. I found it useful as an intermediate step that Z shell is more flexible than other shells about where to put redirection, so: < foo.txt | wc -l works in zsh instead of cat foo.txt (to get line count without a filename, which is useful in shell scripts and long one-liners), and seeing that, I would see more obviously that the pipeline is unnecessary.