chflags -R uchg directory
chflags -R nouchg directory

$ ls -lO
-rw-r--r-- 1 user staff uchg 0 Dec 13 07:19 locked_file
-rw-r--r-- 1 user staff -    0 Dec 13 07:19 unlocked_file

Unlike the Read-only attribute for a file, the Read-only attribute for a folder is typically ignored by Windows, Windows components and accessories, and other programs. For example, you can delete, rename, and change a folder with the Read-only attribute by using Windows Explorer. The Read-only and System attributes is only used by Windows Explorer to determine whether the folder is a special folder, such as a system folder that has its view customized by Windows (for example, My Documents, Favorites, Fonts, Downloaded Program Files), or a folder that you customized by using the Customize tab of the folder's Properties dialog box.

/mac | Dec 13, 2009