diff --git a/os-util.go b/os-util.go
index 228388c..bb9c03b 100644
--- a/os-util.go
+++ b/os-util.go
@@ -132,7 +132,7 @@ func MakeParentDir(filePath string) (dir string, err error) {
 	dir = filepath.Dir(filePath)
 	if !IsDirectory(dir) {
 		if err1 := os.MkdirAll(dir, 0755); err1 != nil {
-			err = fmt.Errorf("Can't make parent path of %#v: %v", filePath, err1)
+			err = fmt.Errorf("can't make parent path of %#v: %v", filePath, err1)
 		}
 	}
 	return
@@ -157,7 +157,7 @@ func ExpandFilePathAndMakeParentV(specPath string, maps ...map[string]string) (e
 func MakeDir(dirPath string) (err error) {
 	if !IsDirectory(dirPath) {
 		if err1 := os.MkdirAll(dirPath, 0755); err1 != nil {
-			err = fmt.Errorf("Can't make directory path %#v: %v", dirPath, err1)
+			err = fmt.Errorf("can't make directory path %#v: %v", dirPath, err1)
 		}
 	}
 	return