diff --git a/HowtoPDF.md b/HowtoPDF.md
index efbc4f1c..cc31144c 100644
--- a/HowtoPDF.md
+++ b/HowtoPDF.md
@@ -31,5 +31,5 @@ Créer un booklet au format A5 :
 
 ~~~
 # apt install psutils
-$  pdf2ps in.pdf - | psbook | psnup -s1 -2 | ps2pdf - out.pdf
+$  pdf2ps in.pdf - | psbook | psnup -2 | ps2pdf - out.pdf
 ~~~