diff --git a/main.go b/main.go
index a6c2dd5..15fdfe0 100644
--- a/main.go
+++ b/main.go
@@ -302,7 +302,7 @@ func licenseHeader(path string, tmpl *template.Template, data licenseData) ([]by
 		lic, err = executeTemplate(tmpl, data, "/**", " * ", " */")
 	case ".cc", ".cpp", ".cs", ".go", ".hcl", ".hh", ".hpp", ".m", ".mm", ".proto", ".rs", ".swift", ".dart", ".groovy", ".v", ".sv":
 		lic, err = executeTemplate(tmpl, data, "", "// ", "")
-	case ".py", ".sh", ".yaml", ".yml", ".dockerfile", "dockerfile", ".rb", "gemfile", ".tcl", ".tf", ".bzl", ".pl", ".pp", "build", ".build", ".toml":
+	case ".py", ".sh", ".yaml", ".yml", ".dockerfile", ".rb", "gemfile", ".tcl", ".tf", ".bzl", ".pl", ".pp", "build", ".build", ".toml":
 		lic, err = executeTemplate(tmpl, data, "", "# ", "")
 	case ".el", ".lisp":
 		lic, err = executeTemplate(tmpl, data, "", ";; ", "")
@@ -328,7 +328,10 @@ func licenseHeader(path string, tmpl *template.Template, data licenseData) ([]by
 		if base == "cmakelists.txt" || strings.HasSuffix(base, ".cmake.in") || strings.HasSuffix(base, ".cmake") {
 			lic, err = executeTemplate(tmpl, data, "", "# ", "")
 		}
-		if base == "Jenkinsfile" || strings.HasSuffix(base, ".groovy") {
+		if base == "jenkinsfile" || strings.HasSuffix(base, ".groovy") {
+			lic, err = executeTemplate(tmpl, data, "", "// ", "")
+		}
+		if base == "dockerfile" || strings.HasSuffix(base, ".dockerfile") {
 			lic, err = executeTemplate(tmpl, data, "", "// ", "")
 		}
 	}