When Apple announced the release of Mac OS X, many Mac users were stunned: here was a new operating system based on the venerable Unix, which, they feared, would call into question the Mac’s legendary ...

Unix was developed as a command line interface in the early 1970s with a very rich command vocabulary. DOS followed more than a decade later for the IBM PC, and DOS commands migrated to Windows.

Not every Unix command sparks with novelty. After all, the OS has now been around for roughly forty years and the spark wears off. But there are some commands that pick up from where the basics run ...