    For each NAME, the full pathname of the command is determined and
    remembered.  If the -p option is supplied, PATHNAME is used as the
    full pathname of NAME, and no path search is performed.  The -r
    option causes the shell to forget all remembered locations.  The -d
    option causes the shell to forget the remembered location of each NAME.
    If the -t option is supplied the full pathname to which each NAME
    corresponds is printed.  If multiple NAME arguments are supplied with
    -t, the NAME is printed before the hashed full pathname.  The -l option
    causes output to be displayed in a format that may be reused as input.
    If no arguments are given, information about remembered commands is displayed.
