diff --git a/doc/stdenv.xml b/doc/stdenv.xml
index 00d1ec870988..da72086640fe 100644
--- a/doc/stdenv.xml
+++ b/doc/stdenv.xml
@@ -715,13 +715,7 @@ passthru.updateScript = [ ../../update.sh pname "--requested-release=unstable" ]
      </para>
      <para>
       For information about how to run the updates, execute
-      <cmdsynopsis>
-       <command>nix-shell</command> 
-       <arg>
-        maintainers/scripts/update.nix
-       </arg>
-      </cmdsynopsis>
-      .
+      <command>nix-shell maintainers/scripts/update.nix</command>.
      </para>
     </listitem>
    </varlistentry>