Terminal

Terminal is an application that allows you to run commands within Mac OS X. It's located within the Applications folder. It is entirely text-based and is very persnickety about typos. You must hit enter after every command within Terminal; you can also use the up and down arrows to scroll through commands you've entered previously.

Files and folders

In Finder, you can see folders and interact with them in a visual manner. Terminal does the exact same thing with words instead of icons.

Picture your folders as a tree: What you see when you double-click the Macintosh HD logo on your desktop is the very base of the tree, and everything branches out from there.

Generally speaking, Terminal will allow you to work with one folder at a time, and you must explicitly tell Terminal which folder you want to use. By default, you'll start in your user folder. Type ls and hit enter to see a list of the files within the folder that's currently active. You should see Documents, Movies, Music, Pictures, etc., just as you would in the Finder window for your user's home folder.

Moving through the file structure

The name of the current folder (or "directory") will always be visible in Terminal, before your username. The command to move among folders is cd, as in "change directory."

If you want to move into your documents folder, for example—which is further out into the branches of the tree—you'd type cd Documents and hit enter.

cd .. moves up a level in the tree—that is, one level closer to the trunk.

If you're in Documents but wanted to open Pictures, you can combine those two commands to go up a level and then follow a different branch:cd ../Pictures.

The cd and ls commands should cover most, if not all, of what you'll need to do in Terminal that isn't already part of Tarbell.