Don't remove temporary files and directories on exit. This is useful
for debugging.
+=item B<--use-installed>
+
+If packages are already installed, use the contents (from the local
+filesystem) instead of downloading them.
+
+Note that this can cause malformed appliances if local files have been
+changed from what was originally in the package. This is particularly
+a problem for configuration files.
+
+However this option is useful in some controlled situations: for
+example when using febootstrap inside a freshly installed chroot.
+
=item B<-v>
=item B<--verbose>