shell builtin
    without using a full pathname.
    
    Options:
      -a	print a list of builtins showing whether or not each is enabled
      -n	disable each NAME or display a list of disabled builtins
      -p	print the list of builtins in a reusable format
      -s	print only the names of Posix `special' builtins
    
    Options controlling dynamic loading:
      -f	Load builtin NAME from shared object FILENAME
      -d	Remove a builtin loaded with -f
    
    Without options, each NAME is enabled.
    
    To use the `test' found in $PATH instead of the shell builtin
    version, type `enable -n test'.
    
    Exit Status:
    Returns success unless NAME is not a shell builtin or an error occurs.