--- a
+++ b/maxima-pre59/bin/move-if-change
@@ -0,0 +1,14 @@
+if
+test -r $2
+then
+if
+cmp $1 $2 > /dev/null
+then
+echo $2 is unchanged
+rm $1
+else
+mv $1 $2
+fi
+else
+mv $1 $2
+fi