In fact, if you use Get Info to display more information, you will see that Kind is listed as Alias and that Original shows the location of the original folder. When you look at a symbolic link in the Finder, it looks just like an alias. We are unable to display it all on one line here. The above text is all on one line when viewed in the Terminal. $ ln -s AFP584Site AFP548Site_link $ ls -l drwxr-xr-x 2 david david 68 13 Jan 10:10 AFP584Site lrwx- 1 david david 8 13 Jan 10:12 AFP548Site_link -> AFP584Site Note that the file mode begins with the lowercase letter l. A long listing shows what the link points to. In the following figure, a symbolic link is created to AFP548Site. You create a symbolic link using ln with the s option.
Symbolic links originated in the UNIX world.
#SYMBOLIC LINKER FOR MAC MAC OS X#
This behavior corrects a problem in Mac OS X v10.1 that prevented aliases from working as expected on volumes restored from a backup copy. Starting with Mac OS X v10.2, alias resolution attempts to resolve the file pathname before attempting to resolve the alias using the file ID.
#SYMBOLIC LINKER FOR MAC PLUS#
In Mac OS X v10.1, alias resolution was based upon an HFS Plus identifier called the file ID. If you re-create the folder in the original location, the alias will point to the new folder. If, instead of moving the original folder, you delete it from the computer completely (for example, by using rm from Terminal), Get Info will show that the alias no longer points to anything. You'll see some of the path information in the output. You can also get data using the strings command: Developer/Tools/DeRez YourAliasFile only alias To see the raw data stored about an alias, issue the following command: You can use the techniques discussed earlier to look at the resource fork of an alias. The file still exists, and an alias will continue to point to it.Īlias data is stored in the resource fork of a file. Keep in mind that dragging a file or folder to the Trash is not deletingit's moving it to the Trash. Mac OS X automatically updates aliases when the original file or folder is moved. Now Original shows the new location of the original folder. If you move the original folder somewhere elsein this case, into the folder called EditedWebSitesand use Get Info to display information about the alias again, you'll see that the information has changed. If you use Get Info to display more information about the alias, you see that Kind is listed as Alias and that Original shows the location of the folder to which it points. The arrow on the folder icon indicates it is an alias. The following figure shows an alias to the folder AFP548. You create an alias to a file or folder using Make Alias from the Finder's File menu. At the very basic level, the Finder understands both aliases and symbolic links but UNIX via the Terminal has no concept of aliases so they show up as a zero byte length file. You can locate links using the find command:Īliases and symbolic links both act as pointers to files and folders, but their behavior is different. Mac OS X makes liberal use of symbolic links. Mac OS X uses symbolic links for each of these folders and so the operating system thinks these folders actually exist at the root level of the boot volume, not one level deep inside private, where they actually exist. private contains other directories like etc, var, tmp, and Network. Some examples of symbolic links in Mac OS X exist because of an extra folder, called private, which was held over from NEXTSTEP.
Classic applications handle symbolic links correctly. Symbolic links are common on UNIX systems. The other is a symbolic link, which you create using the command line. One is an alias, which you create in the Finder. You can use two types of files on Mac OS X to access files and folders indirectly.
You may have multiple versions of a document or folder and want a link called Latest to always point to the most current one. You may have a script or program that depends on a file-system hierarchy that's different from what you have. Sometimes you want users to be able to access a file by a different name, or from a different file-system location than the one in which it actually resides.
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