[This is a repost from my HackTheDay blog of 6 years ago. But these are rare-to-find tips that are still highly valuable.]
You don’t really need a reason to try out these Mac OSX tips and hacks. But they are fun, probably useful and definitely will get a nice reaction from your friends. They all involve typing some commands in the Terminal.app(each command is followed by the Enter key); if commands start with sudo, you might be asked to also type down your Mac administrator password(which you ought to have set when you first logged to your computer). For instructions on finding Terminal.app and tips on using it, see our great Terminal.app tutorial.