Learning Unix for Mac OS X, Second Edition

Chapter 2. Using Unix

Once you launch Terminal, you can use the many facilities that Mac OS X provides. As a user, you have an account that gives you:

• A place in the filesystem where you can store your files

• A username that identifies you and lets you control access to your files

• An environment you can customize

The Mac OS X Filesystem

A file is the unit of storage in Mac OS X. A file can hold anything: text (a report you’re writing, a to-do list), a program, digitally encoded pictures or sound, and so on. All of those are just sequences of raw data until they’re interpreted by the right program.

Files are organized into directories (more commonly referred to as a folder on the Mac). A directory is actually a special kind of file where the system stores information about other files. You can think of a directory as a place, so that files are said to be contained in directories, and you work inside a directory.

A filesystem includes all the files and directories on a mounted volume, such as your system’s hard disk or your iDisk. This section introduces the Mac OS X filesystem. Later sections show how you can look in files and protect them. Chapter 3 has more information.

Your Home Directory

When you launch Terminal, you’re placed in a directory called your home directory . This directory, which can be opened in the Finder by clicking the Home icon, contains personal files, application preferences, and application data such as bookmarks. In your home directory, you can create your ...