Top 20 OS X command-line secrets for power users

For most people, the Mac's OS X is all about the graphical user interface. But system administrators and power users know that the Mac's command-line interface can be a powerful time saver and, in many cases, the only method to accomplish certain tasks. The command shell itself, delivered by Apple's included lTerminal program, is a wonder of open source. Bash -- for "Bourne again shell" -- was developed by free-software guru Brian Fox. It's widely used on operating systems of all kinds, including iOS, Linux, Unix, and mainframes. There's already a huge brain trust of tool knowledge around using Bash as a systems administrator's command shell.