diff --git a/Dockerfile b/Dockerfile
index 312afe8..1e46586 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -46,8 +46,9 @@ RUN { \
     echo ''; \
     echo '    debug := os.Getenv("DEBUG") != ""'; \
     echo '    if debug {'; \
-    echo '        fmt.Fprintf(os.Stderr, "[sendmail] relay=%s port=%s sender=%s recipients=%v\n", relay, port, sender, recipients)'; \
-    echo '        fmt.Fprintf(os.Stderr, "[sendmail] body:\n%s\n", body)'; \
+    echo '        fmt.Fprintln(os.Stderr, fmt.Sprintf("[sendmail] relay=%s port=%s sender=%s recipients=%v", relay, port, sender, recipients))'; \
+    echo '        fmt.Fprintln(os.Stderr, "[sendmail] body:")'; \
+    echo '        fmt.Fprintln(os.Stderr, string(body))'; \
     echo '    }'; \
     echo ''; \
     echo '    if err = smtp.SendMail(relay+":"+port, nil, sender, recipients, body); err != nil {'; \