diff --git a/doc/default.nix b/doc/default.nix
index b68194b97a7b..004ffb70b749 100644
--- a/doc/default.nix
+++ b/doc/default.nix
@@ -19,7 +19,7 @@ stdenv.mkDerivation {
   '';
 
   buildCommand = ''
-    ln -s $sources/*.xml . # */
+    ln -s "$sources/"*.xml .
 
     echo ${nixpkgsVersion} > .version
 
@@ -37,7 +37,7 @@ stdenv.mkDerivation {
     cp ${./style.css} $dst/style.css
 
     mkdir -p $dst/images/callouts
-    cp ${docbook5_xsl}/xml/xsl/docbook/images/callouts/*.gif $dst/images/callouts/
+    cp "${docbook5_xsl}/xml/xsl/docbook/images/callouts/"*.gif $dst/images/callouts/
 
     mkdir -p $out/nix-support
     echo "doc manual $dst manual.html" >> $out/nix-support/hydra-build-products