diff --git a/build.go b/build.go
index a78ded3..f43a818 100644
--- a/build.go
+++ b/build.go
@@ -137,6 +137,7 @@ func GfmrunActionFunc(c *cli.Context) error {
 	if err != nil {
 		return err
 	}
+	defer file.Close()
 
 	var counter int
 	scanner := bufio.NewScanner(file)