diff --git a/chapter11/reboot.xml b/chapter11/reboot.xml
index 1d76fcc7a..809d9bb70 100644
--- a/chapter11/reboot.xml
+++ b/chapter11/reboot.xml
@@ -107,7 +107,7 @@
   <para>Then unmount the virtual file systems:</para>
 
 <screen><userinput>umount -v $LFS/dev/pts
-umount -v $LFS/dev/shm
+mountpoint -q $LFS/dev/shm &amp;&amp; umount $LFS/dev/shm
 umount -v $LFS/dev
 umount -v $LFS/run
 umount -v $LFS/proc