Index: scripts/xflock4
===================================================================
--- scripts/xflock4	(revision 29672)
+++ scripts/xflock4	(working copy)
@@ -19,11 +19,18 @@
 #  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 #
 
-if test x"`which xscreensaver-command 2>/dev/null`" != x""; then
-    xscreensaver-command -lock 
-elif test x"`which gnome-screensaver-command 2>/dev/null`" != x""; then
-    gnome-screensaver-command --lock
-else
-    xlock $*
+# Try xscreensaver first
+if [ -x $(which xscreensaver-command 2>/dev/null) ]; then
+    xscreensaver-command -lock 2>/dev/null && exit 0
 fi
-exit 0
+# Next gnome-screensaver
+if [ -x $(which gnome-screensaver-command --lock 2>/dev/null) ]; then
+    gnome-screensaver-command --lock 2>/dev/null && exit 0
+fi
+# Then slock
+if [ -x $(which slock 2>/dev/null) ]; then
+    slock 2>/dev/null && exit 0
+fi
+# Fallback to xlock
+xlock $* && exit 0
+