Highlighting an icon and then choosing File → Make Alias (or pressing ⌘-L), generates an alias, a specially branded duplicate of the original icon (see Figure 2-7). It's not a duplicate of the file—just of the icon; therefore it requires negligible storage space. When you double-click the alias, the original file opens. (A Macintosh alias is essentially the same as a Windows shortcut.)
Because you can create as many aliases as you want of a single file, aliases let you, in effect, stash that file in many different folder locations simultaneously. Double-click any one of them, and you open the original icon, wherever it may be on your system.
You can also create an alias of an icon by Option-⌘-dragging it out of its window. (Aliases you create this way lack the word alias on the file name—a distinct delight to those who find the suffix redundant and annoying.) You can also create an alias by Control-clicking a normal icon and choosing Make Alias from the shortcut menu that appears, or by highlighting an icon and then choosing Make Alias from the Action menu.
An alias takes up almost no disk space, even if the original file is enormous. Aliases are smart, too: even if you rename the alias, rename the original file, move the alias, and move the original around on the disk, double-clicking the alias still opens the original icon.