diff --git a/examples/prd/README b/examples/prd/README
new file mode 100644
index 0000000000..7733df9a78
--- /dev/null
+++ b/examples/prd/README
@@ -0,0 +1,3 @@
+run this example as:
+
+mpirun -np 4 lmp_linux -partition 4x1 -in in.prd