The Beginner’s Guide to Command Line Magic

Many of you may have heard of the supposed power of Mac OS X that it gains from Unix-y underpinnings. Like one of those proclamations that make you seem smart, but you’re not sure why (“Red wine is good for you because it has antioxidants,” you say with an air of superiority), the BSD-like innards of OS X are something that Mac enthusiasts like to cite, but rarely get their hands dirty in.

So for those of you who have always wondered how to make your life a little easier or more powerful or impressive with command line voodoo, I am putting together a little beginner’s guide here. This is truly a beginner’s guide, so those of you who know a little bit about this stuff may want to wait until I get to part 3 or 4 of this series.

Why?
You may be wondering why you would possibly need to enter commands on a text prompt when OS X has all this wonderful GUI-ness. Everyone has their own reasons—Matrix-y coolness being only one of them. There are a few good reasons, in no particular order:

• GUIs can get bogged down. Who will let you debug and/or fix that situation without a reboot? Terminal.app!
• GUIs are no good for repetitive small tasks.
• GUIs are no good for chaining small tasks together. You can take the output of one command and feed it into the next effortlessly. Say you have one command that lists the currently running programs (ps) and another that searches for lines with a particular string (grep). Now, in one single line, you can put them together to search for all running applications that contain the string “Microsoft”—ps | grep Microsoft. That’s it.

Basics
To run anything on the command line in standard OS X boxes, you need to launch Terminal.app. When you get better at this stuff, go get iTerm and use it instead. If you’re a really keen newbie, you will keep Terminal.app in your Dock.

Each command can have “arguments” and “options.” Arguments are usually the object you want the command to act on. Options usually specify how you want it to perform a specific task. For example, ls lists contents of the current directory. If you give it the argument /Users/ by saying ls /Users/ it will list the contents of the /Users directory. If you give it the option ‘-l’ by saying ls -l /Users it will give you a lot more information about the files it lists. You can usually chain together many options, and for many commands, you can chain together many arguments as well.

man
Simple Usage: man