MacOS – Icon? file on OS X desktop

desktoplsmacosterminal

When I ls my Desktop from terminal (by using ls ~/Desktop), I see a file named Icon?. As far as I can tell, it's empty (nano Icon? shows nothing). It doesn't show up on my actual Desktop, and open Icon? shows the Finder alert

This item is used by Mac OS X and can't be opened

Here is the output from mdls Icon?:

kMDItemContentType         = ""
kMDItemFSContentChangeDate = 2009-09-23 13:32:52 -0600
kMDItemFSCreationDate      = 2009-09-20 07:27:46 -0600
kMDItemFSCreatorCode       = "MACS"
kMDItemFSFinderFlags       = 16384
kMDItemFSHasCustomIcon     = 0
kMDItemFSInvisible         = 1
kMDItemFSIsExtensionHidden = 0
kMDItemFSIsStationery      = 0
kMDItemFSLabel             = 0
kMDItemFSName              = "Icon "
kMDItemFSNodeCount         = 0
kMDItemFSOwnerGroupID      = 20
kMDItemFSOwnerUserID       = 501
kMDItemFSSize              = 0
kMDItemFSTypeCode          = "icon"

Does anyone have an idea as to what this is?

Best Answer

What is it?

It's name is actually Icon\r, with \r being the carriage return 0x0D. If letting the shell autocomplete the path in Terminal, it yields Icon^M, ^M being \r.

Icon^M is a file existing in all directories that have a custom icon in Finder. If you change a directory's icon e.g. in its Get Info dialog by pasting an image into the icon in the upper left corner, the Icon^M file is created.

Changing a volume's icon creates a hidden .VolumeIcon.icns file instead.

Why is it invisible?

It's invisible in Finder, because its hidden attribute is set.

$ ls -lO Icon^M 
-rw-r--r--@ 1 danielbeck  staff  hidden 0 24 Apr 23:29 Icon?

Change with chflags nohidden Icon^M.

Where is its data?

While the file's data fork (i.e. content) is empty (i.e. a file size of 0 bytes in Terminal), the actual icon data is stored in the file's resource fork.

$ ls -l@ Icon^M
    com.apple.ResourceFork  350895

You can copy the resource fork to a file (to view e.g. in a hex editor) like this:

$ cp Icon^M/..namedfork/rsrc Icondata

How can I view it?

The easiest way to get the image is to copy the icon from the Get Info dialog of the folder it's contained in into the clipboard, and then create a new image from clipboard in Preview (Cmd-N). It's an icns image then by default.

Its format is icns, encoded as an icon resource with derez. If you open it in a hex editor and remove the first 260 bytes (so the file begins with the icns magic byte-string), you can open it in Preview.app. Alternatively you can open it with XnView

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