Fix a typo. Fixes #1921.

git-svn-id: http://svn.linuxfromscratch.org/LFS/trunk/BOOK@7868 4aa44e1e-78dd-0310-a6d2-fbcd4c07a689

chapter06/udev.xml

@@ -38,7 +38,7 @@
     <para>The udev-config tarball contains LFS-specific files used to configure
     Udev. Unpack it into the Udev source directory:</para>
 
-<screen><userinput>tar xf ../&udev-config;.tar.bz2</userinput></screen>
+<screen><userinput>tar -xf ../&udev-config;.tar.bz2</userinput></screen>
 
     <para>Create some devices and directories that Udev cannot handle due to
     them being required very early in the boot process:</para>