diff --git a/lkmpg.tex b/lkmpg.tex
index 3024f200..10b3d55d 100644
--- a/lkmpg.tex
+++ b/lkmpg.tex
@@ -1347,14 +1347,14 @@ \section{sysfs: Interacting with your module}
 What is the current value of \cpp|myvariable| ?
 
 \begin{codebash}
-cat /sys/kernel/mymodule/myvariable
+sudo cat /sys/kernel/mymodule/myvariable
 \end{codebash}
 
 Set the value of \cpp|myvariable| and check that it changed.
 
 \begin{codebash}
-echo "32" > /sys/kernel/mymodule/myvariable
-cat /sys/kernel/mymodule/myvariable
+echo "32" | sudo tee /sys/kernel/mymodule/myvariable
+sudo cat /sys/kernel/mymodule/myvariable
 \end{codebash}
 
 Finally, remove the test module: