sticky bit

sticky bit

   <operating system> The {bit} in the mode of a {Unix} file
   which, if set for an executable, tells the {kernel} to keep
   the code loaded in {swap space} even after it has finished
   executing on the assumption that it is likely to be used again
   soon.  This performance optimisation was included in some
   early (and recent?) versions of {Unix} to save reloading
   frequently used programs such as the {shell} or {vi} from
   disk.

   If the sticky bit is set on a directory, an unprivileged user
   may not delete or rename files of other users in that
   directory even if he has write access to the directory.

   The Unix "ls" command displays a set sticky bit as a "t" in
   the permissions of a file or directory.

   (1997-02-26)