+=item EDITOR
+
+The C<edit> command uses C<$EDITOR> as the editor. If not
+set, it uses C<vi>.
+
+=item HOME
+
+If compiled with GNU readline support, then the command history
+is saved in C<$HOME/.guestfish>
+
+=item LIBGUESTFS_APPEND
+
+Pass additional options to the guest kernel.
+