diff --git a/Dockerfile b/Dockerfile
index 39ef329..6ff1583 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -2,6 +2,11 @@ FROM golang:1.16 AS build
 
 WORKDIR /app
 
+# set env
+RUN go env -w GO111MODULE=on
+RUN go env -w GOPROXY=https://goproxy.cn,direct
+
+# cache dependencies
 COPY go.mod go.sum ./
 RUN go mod download
 
diff --git a/main.go b/main.go
index b4cdd69..5b7081f 100644
--- a/main.go
+++ b/main.go
@@ -315,6 +315,8 @@ func licenseHeader(path string, tmpl *template.Template, data licenseData) ([]by
 		// handle various cmake files
 		if base == "cmakelists.txt" || strings.HasSuffix(base, ".cmake.in") || strings.HasSuffix(base, ".cmake") {
 			lic, err = executeTemplate(tmpl, data, "", "# ", "")
+		} else if base == "Makefile" || base == "makefile" || strings.HasSuffix(base, ".mk") { // handle various make files
+			lic, err = executeTemplate(tmpl, data, "", "# ", "")
 		}
 	}
 	return lic, err
@@ -374,7 +376,11 @@ func hasLicense(b []byte) bool {
 	if len(b) < 1000 {
 		n = len(b)
 	}
-	return bytes.Contains(bytes.ToLower(b[:n]), []byte("copyright")) ||
+	return bytes.Contains(bytes.ToLower(b[:n]), []byte("# copyright")) ||
+		bytes.Contains(bytes.ToLower(b[:n]), []byte("copyright ")) ||
+		bytes.Contains(bytes.ToLower(b[:n]), []byte("// copyright")) ||
+		bytes.Contains(bytes.ToLower(b[:n]), []byte("/* copyright")) ||
+		bytes.Contains(bytes.ToLower(b[:n]), []byte("* copyright")) ||
 		bytes.Contains(bytes.ToLower(b[:n]), []byte("mozilla public")) ||
 		bytes.Contains(bytes.ToLower(b[:n]), []byte("spdx-license-identifier"))
 }
diff --git a/main_test.go b/main_test.go
index b2ed227..868be31 100644
--- a/main_test.go
+++ b/main_test.go
@@ -340,7 +340,7 @@ func TestLicenseHeader(t *testing.T) {
 			"(**\n   HYS\n*)\n\n",
 		},
 		{
-			[]string{"cmakelists.txt", "f.cmake", "f.cmake.in"},
+			[]string{"cmakelists.txt", "f.cmake", "f.cmake.in", "makefile", "Makefile", "f.mk"},
 			"# HYS\n\n",
 		},
 
@@ -395,6 +395,10 @@ func TestHasLicense(t *testing.T) {
 
 		{"Copyright 2000", true},
 		{"CoPyRiGhT 2000", true},
+		{"// Copyright 2000", true},
+		{"# CopyRight 2000", true},
+		{"/*\n * CopyRight 2000", true},
+		{"// SPDX-License-Identifier: MIT", true},
 		{"Subject to the terms of the Mozilla Public License", true},
 		{"SPDX-License-Identifier: MIT", true},
 		{"spdx-license-identifier: MIT", true},