In GAP 4, the -l option is used to specify the root directory
(see GAP Root Directory in the Reference Manual)
of the GAP distribution,
which is the directory containing the lib and doc subdirectories.
Note that in GAP 3 this option was used to specify the path to the
lib directory.
The -h option of GAP 3 has been removed,
the path(s) for the documentation are deduced automatically in GAP 4.
The option -g is now used to print information only about full garbage
collections.
The new option -g -g generates information about partial
garbage collections too.
GAP 4 manual