diff --git a/build_gesso.sh b/build_gesso.sh
index 5c04d5b155931b6cf6d1da515e77416bb8d66a5b..a4994dd8232d1007f72c665e151ce4a9dad84987 100755
--- a/build_gesso.sh
+++ b/build_gesso.sh
@@ -6,11 +6,11 @@ git checkout $gesso_version
 cd ..
 
 if [ -f "gulpfile.js" ]; then
-  mv gulpfile.js gesso
+  cp gulpfile.js gesso
 fi
 
 if [ -f "packages.json" ]; then
-  mv packages.json gesso
+  cp packages.json gesso
 fi
 
 ln -s "gesso/source" "source"