The Finder maintains certain information about files, folders, and volumes. Among this data are attributes called flags. It is not normally necessary to change an item's Finder flags.
An item with the Locked flag can not be modified. File content is read-only and items can not be put into or moved out of locked folders; items within such folders are unaffected. Setting the Locked flag for volumes is not recommended.
The purpose of this flag is to lock names to prevent inadvertently changing them in the Finder. However, Finder has ignored this flag since Mac OS X 10.4.6.
Items with this flag set can not be seen in the Finder.
Files and folders whose names begin with a period, such as “.DS_Store” files, are always invisible. The only way to make such files visible is to rename them. Most such files are system files, and renaming them is inadvisable.
Extreme caution should be used when setting the Invisible flag on a volume; once a volume is invisible, it is difficult to restore its visibility. Files and folders on an invisible volume cannot be accessed in Finder or from open file dialogs.
This flag is set if the Finder displays the item with a custom icon.
This flag determines whether a file's extension appears in the Finder. It does not change how any other application sees the name. A Finder preference can be set to ignore this flag.
This flag is set if the file is a Finder alias.
Changing the status of the alias flag is not recommended unless it is not set correctly. If its alias bit is not set correctly, a file or alias will not work as expected.
This flag is set if the file is stationary.
The package flag is used by the Mac OS 9 Finder to determine whether to treat the folder as a package. A package appears in the Finder as a single file. To be a valid Mac OS 9 package, a folder’s contents must meet specific requirements. The package flag is rarely used in Mac OS X, and most packages in Mac OS X do not have this flag set. In Mac OS X, an item is normally treat as a package if its extension has been registered as belonging to a package. You can set the package bit on a folder to cause Mac OS X to treat it as a package even if no software installed on that computer has registered its extension for a package. This can be useful if a package was copied to a computer that doesn’t recognize it as a package.
