Terminal provides a command line interface to control the UNIX based operating system that lurks below OS X. Here's everything you need to know about terminal, and what it can do for you and your Mac.
Of all the tools tucked away in OS X's Utilities folder, few are as mis-understood as Terminal. At first glance, it's the very antithesis of what the Mac is all about. Isn't the whole point of a graphical user interface that we don't need to concern ourselves with learning arcane instructions and typing them on a command line? Well, yes it is, but learning those commands and using them allows you to customise elements of your Mac, perform tasks that would otherwise be cumbersome or require additional software, and troubleshoot quickly when things go awry.
What is Mac Terminal?
The first thing to understand about Terminal is that it's just an application and it lives in the Utilities folder in Applications. You launch it like any other and when you do, you'll see Apple's implementation of a Unix command-line environment, known as a shell. There are various types of shell; Apple uses one called Bash.
The title bar of a Terminal window displays the name of the current user, the type of shell, and the size of the window in pixels. If you look at the command-line inside the window, you'll see that each line starts with the name of the Mac and is followed by the name of the current user. The 'cursor' is indicated by a shaded box.
You can run other shells with Terminal, but you'll have to install those yourself. Commands in Unix are shell-specific, so it's important, say when you're following tips written for a different flavour of Unix, that you use the right shell for the commands, or vice versa.
How to use Terminal on a Mac
We're getting ahead of ourselves, however. Using Terminal is straightforward, you type a command on the command-line and press Return to execute it. A command has three elements to it; the command itself, which calls a specific tool, an option which modifies the command's output, and an argument, which calls the resource on which the command will operate.
Often, the argument takes the form of a specific file, in which case you need to type the file path at the end of the command. There is a shortcut, however. If you locate the file in the Finder, you can drag and drop it onto the Terminal window and Terminal will extract its path and slot it into the command for you.
There are a few rules that you need to bear in mind when using any command-line interface. One of these is that every character, including spaces, matters. So if you copy a command from a website, magazine, or book, you need to make sure you type it exactly as it's shown.
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