Working with Files and Folders

Working with files and folders under Mac OS X is quite similar to working with them under previous versions.

Under Mac OS X, you can move and copy files and folders as in previous versions of the OS. Just drag the folders or files to where you want them to reside.

To place a copy of an item in a different folder, hold down the Option key while you drag the item. To duplicate an item (make a copy of it in its current location), select it and select File, Duplicate (or press graphics/mac.gif-D).


The Columns view is one of the more useful for moving files and folders around because it gives you a good view of the entire hierarchy of the volume you are working with.

You can also create copies of files and folders using the contextual menu commands and the commands on the Edit menu. You can place a copy of the items in a new location by pasting them there.



One improvement included in version 10.3 is that folders become highlighted so you can easily see in which folder the item you are moving will be placed. This is especially useful when you are viewing Finder windows in the Columns view.

Creating and naming folders is another area in which Mac OS X uses the same model as previous versions. One thing that is new under Mac OS X is the allowable length for folder names, which is now 256 characters. Of course, you aren't likely to ever use a folder name that long because it would be very difficult to read, but at least you have more flexibility with folder names than you did previously.

To name a folder or edit its current name, select the folder and press Return. The folder's name becomes highlighted and you can create a new name.

Other tasks you do with Mac OS X are similar to previous versions as well, including those discussed in the following three sections.

Naming Files

Naming files is very similar to naming folders, with one exception. Because the underlying architecture of the Mac OS has changed, many document names now include filename extensions?for example, .doc at the end of a Word document filename.

Long known in the PC world, file extensions are a code that helps identify a file's type and thus the application used to view or edit that file. Many Mac OS X applications also use filename extensions; the OS uses these extensions to launch the appropriate application for that document when you open the file.

To understand more about filename extensions under Mac OS X, see "Saving Documents in Mac OS X," p. 174.

When you name a document from within an application that uses filename extensions, the correct extension is appended automatically to the filename you enter. However, when you rename files on the desktop or in a Finder window, you need to be aware of a filename's extension if it has one (not all applications use an extension).

A complication in this is that you can choose to show or hide filename extensions on a file-by-file basis or at the system level. However, filename extensions are almost always in use, whether you can see them or not. Hiding them simply hides them from your view.

I wrote "almost always in use" because all Mac OS X applications add filename extensions to files with which they work. And most Classic applications do not use filename extensions. Fortunately, you can use the Info tool to associate applications with specific files so the lack of a proper filename extension is not a significant problem.

To learn how to associate files with specific applications, see "Opening Documents in Mac OS X," p. 166.

If you want to rename a file that has an extension, you should leave the extension as it is. If you change or remove the extension, the application you use to open the file might not be launched automatically when you try to open the file.

The filename extensions you see under Mac OS X include some of the three- or four-letter filename extensions with which you are no doubt familiar, such as .doc, .xls, .html, .jpg, .tiff, and so on. However, there are many, many more filename extensions you will encounter. Some are relatively short, whereas others (particularly those in the system) can be quite long. There isn't really any apparent rhyme or reason to these filename extensions so you just have to learn them as you go. Because you will mostly deal with filename extensions that are appended by an application when you save a document, this isn't a critical task. However, as you delve deeper into the system, you will become more familiar with many of the sometimes bizarre-looking filename extensions Mac OS X uses.


Depending on the file type, some files open properly even if you do remove or change the file's extension. But it is better to be safe than sorry, so you should usually leave the file extension as you find it.

You can choose to hide or show filename extensions globally or on an item-by-item basis. To configure filename extensions globally, use the following steps:

  1. Select Finder, Preferences to open the Finder Preferences window.

  2. Click the Advanced tab.

  3. To globally show filename extensions, check the "Show all file extensions" check box.

  4. To allow filename extensions to be shown or hidden for specific items, uncheck the "Show all file extensions" check box.

  5. Close the Preferences window.

To learn how to show or hide filename extensions for specific items, see "Working with Name and Extension Information," p. 110.

Creating and Using Aliases

As with previous versions of the Mac OS, an alias is a pointer to a file, folder, or volume. Open an alias and the original item opens. The main benefits to aliases are that you can place them anywhere on your Mac and that they are very small, so you can use them with little storage penalty.

There are several ways to create an alias, including

  • Select an item and select File, Make Alias.

  • Select an item and press graphics/mac.gif-L.

  • Hold down the Option and graphics/mac.gif keys while you drag an item.

  • Open the Action menu for an item and select Make Alias.

  • Open the contextual menu for an item and select Make Alias.

You might need to find the original from which an alias was created. For example, if you create an alias to an application, you might want to be able to move to that application in the Finder. Do the following:

  1. Select the alias.

  2. Select File, Show Original (or press graphics/mac.gif-R). A Finder window containing the original item opens.

Occasionally, an alias breaks, meaning your Mac loses track of the original to which the alias points. The most common situation is that you have deleted the original, but it can happen for other reasons as well. When you attempt to open a broken alias, you will see a warning dialog box that provides the following three options:

  • Delete Alias? If you click this button, the alias is deleted.

  • Fix Alias? If you click this one, you can use the Fix Alias dialog box to select another file to which you want the alias to point.

  • OK? If you click OK, the dialog box disappears and no changes are made to the alias.

Trashing Files and Folders

Under Mac OS X, the Trash is located at the right end of the Dock. Other than that, the Trash mostly works the same way it always has.

To move something to the Trash, use one of the following methods:

  • Drag the item to the Trash on the Dock.

  • Select an item, open its contextual menu, and select Move to Trash.

  • Select an item and select File, Move to Trash.

  • Select an item and press graphics/mac.gif-Delete.

After you have placed an item in the Trash, you can access it again by clicking the Trash icon on the Dock. A Finder window displaying the Trash directory opens, and you can work with the items it contains.

When you want to delete the items in the Trash, do so in one of the following ways:

  • Select Finder, Empty Trash. In the confirmation dialog box, click either OK (or press Return) to empty the Trash or Cancel to stop the process. You can skip the confirmation dialog box by holding down the Option key while you select Empty Trash.

  • Open the Trash's Dock contextual menu and select Empty Trash on the resulting pop-up.

  • Press Shift-graphics/mac.gif-Delete. In the confirmation dialog box, click either OK (or press Return) to empty the Trash or Cancel to stop the process. You can skip the confirmation dialog box by pressing Option-Shift-graphics/mac.gif-Delete instead.

To permanently disable the warning dialog box when you empty the Trash, perform the following steps:

  1. Select Finder, Preferences to open the Finder Preferences window.

  2. Click the Advanced tab.

  3. Uncheck the "Show warning before emptying the Trash" check box.

  4. Close the Preferences dialog box. The warning no longer appears, no matter how you empty the Trash.


Under Mac OS X version 10.3, you can securely delete items from the Trash. When you do, the data that makes up those items is overwritten so it can't be recovered. To perform a secure delete, place items in the Trash and select Finder, Secure Empty Trash.

    Part I: Mac OS X: Exploring the Core
    Part III: Mac OS X: Living the Digital Life