diff --git a/scripts/build b/scripts/build
index 71879bc..4d09840 100755
--- a/scripts/build
+++ b/scripts/build
@@ -11,5 +11,5 @@ find public \
     -name '*.css' -or \
     -name '*.map' -or \
     -name '*.pdf' | \
-    awk '{print "zopfli "$0;print "brotli "$0}' | \
-      xargs -P$(nproc) -I{} $SHELL -c {}
+      tee >(xargs -n1 -P$(nproc) zopfli) | \
+      xargs -n1 -P$(nproc) brotli