+# Also warn if there's a Debian package installed.
+#
+debnames="xscreensaver xscreensaver-data xscreensaver-data-extra"
+debv=''
+for dpkg in $debnames ; do
+ if test -z "$debv"; then
+ debv=`dpkg -s $dpkg 2>/dev/null | sed -n 's/^Version: \(.*\)$/\1/p'`
+ fi
+done
+
+if test \! -z "$debv" ; then
+ debbdir=`dpkg -L $debnames 2>/dev/null | \
+ sed -n 's@^\(.*/bin/\)xscreensaver$@\1@p'`
+ debhdir=`dpkg -L $debnames 2>/dev/null | \
+ sed -n 's@^\(.*/\)popsquares$@\1@p'`
+ if test -z "$debbdir" ; then debbdir='???'; fi
+ if test -z "$debhdir" ; then debhdir='???'; fi
+
+ warning=no
+ warnL "There is already an installed dpkg of xscreensaver"
+ warn2 "version \"$debv\" on this system."
+ echo ""
+ warn2 "The dpkg was installed in $debbdir,"
+ warn2 "with demos in $debhdir."
+fi
+
+