diff --git a/gnuplot/README.md b/gnuplot/README.md
index d64accd..b85fe8f 100644
--- a/gnuplot/README.md
+++ b/gnuplot/README.md
@@ -6,7 +6,7 @@
     usage:
       gnuplot line.gp                       run line.gp script
       gnuplot -p line.gp                    run script and kepp figure open
-      gnuplot -e "file='data.dat'; column1=1; column2=2; format=''; out=''" line.gp
+      gnuplot -e "file='data.dat'; column1=1; column2=2; format='png'; out='line.png'" line.gp
                                             run script with altered variables
 
 [line.gp](./line.gp)