diff --git a/script/build b/script/build
index bf0abb3766c91ec128cca23adf11a4ee55c353ae..724b76c56867c48ab475013fba6850af662c383e 100755
--- a/script/build
+++ b/script/build
@@ -28,7 +28,7 @@ setup_gopath() {
 }
 
 find_source_files() {
-  find . -maxdepth 2 -name '*.go' -not -name '*_test.go' "$@"
+  find . -maxdepth 2 -name '*.go' '!' -name '*_test.go' "$@"
 }
 
 count_changed_files() {