diff --git a/Makefile b/Makefile
index e4f9d619b9f97deb2be2e1448d584e96e6114ca4..bbdd3748d1e6142e9f8f249848b85cd7668f3e72 100644
--- a/Makefile
+++ b/Makefile
@@ -1,3 +1,7 @@
+## Copyright 2022 schukai GmbH. All rights reserved.
+## Use of this source code is governed by a AGPL-3.0
+## license that can be found in the LICENSE file.
+
 PROJECT_ROOT:=$(dir $(realpath $(lastword $(MAKEFILE_LIST))))
 THIS_MAKEFILE:=$(word $(words $(MAKEFILE_LIST)),$(MAKEFILE_LIST))
 THIS_MAKEFILE_PATH:=$(PROJECT_ROOT)$(THIS_MAKEFILE) 
diff --git a/api.go b/api.go
index ddc7e43a7775146b753ca2baca958966ea39a7b8..5501b77d56929219ff54ed6f7041ec83159609ff 100644
--- a/api.go
+++ b/api.go
@@ -1,3 +1,7 @@
+// Copyright 2022 schukai GmbH. All rights reserved.
+// Use of this source code is governed by a AGPL-3.0
+// license that can be found in the LICENSE file.
+
 package xflags
 
 import (
diff --git a/api_test.go b/api_test.go
index dc7adc98f438a0680c492662aea648445054ff28..eb85229e7337850f9e6f05190669e2c18b7e20aa 100644
--- a/api_test.go
+++ b/api_test.go
@@ -1,3 +1,7 @@
+// Copyright 2022 schukai GmbH. All rights reserved.
+// Use of this source code is governed by a AGPL-3.0
+// license that can be found in the LICENSE file.
+
 package xflags
 
 import (
diff --git a/command.go b/command.go
index cbfcbe7b2a94f5157f163364cb3831adec1a3a40..e7dc0ecdae00f92413fc0b7c00dcefb6ee3ee908 100644
--- a/command.go
+++ b/command.go
@@ -1,3 +1,7 @@
+// Copyright 2022 schukai GmbH. All rights reserved.
+// Use of this source code is governed by a AGPL-3.0
+// license that can be found in the LICENSE file.
+
 package xflags
 
 import (
diff --git a/command_test.go b/command_test.go
index e44467c664e9613777f2d6a6acf31ba16158b1ca..79a34f254f0d9363364bd56e0b480f6456db1073 100644
--- a/command_test.go
+++ b/command_test.go
@@ -1,3 +1,7 @@
+// Copyright 2022 schukai GmbH. All rights reserved.
+// Use of this source code is governed by a AGPL-3.0
+// license that can be found in the LICENSE file.
+
 package xflags
 
 import (
diff --git a/doc.go b/doc.go
index 3e7422784387fdb6bf6047c882136ecde828aee8..cc88bfa852292bf41d7d0a353272cedae8f1795e 100644
--- a/doc.go
+++ b/doc.go
@@ -1,8 +1,8 @@
-// Copyright schukai GmbH. All rights reserved.
-// Use of this source code is governed by a GNU AGPLv3
+// Copyright 2022 schukai GmbH. All rights reserved.
+// Use of this source code is governed by a AGPL-3.0
 // license that can be found in the LICENSE file.
 
 // This package provides a simple way to create a CLI application
-// with subcommands.
+// with subcommands. It is based on the flags package from
 
 package xflags
diff --git a/error.go b/error.go
index be4a46f0bcd21d6855cacff299185ae084fa307e..b8c4678cc7067b0c74085ce124b5f3fb450c375d 100644
--- a/error.go
+++ b/error.go
@@ -1,3 +1,7 @@
+// Copyright 2022 schukai GmbH. All rights reserved.
+// Use of this source code is governed by a AGPL-3.0
+// license that can be found in the LICENSE file.
+
 package xflags
 
 import (
diff --git a/error_test.go b/error_test.go
index 62663211c5f35cdd6b14f81972a732193eaaee3d..a283dc16b13ed03c45059c2ba9170fdc8d1bfcb0 100644
--- a/error_test.go
+++ b/error_test.go
@@ -1,3 +1,7 @@
+// Copyright 2022 schukai GmbH. All rights reserved.
+// Use of this source code is governed by a AGPL-3.0
+// license that can be found in the LICENSE file.
+
 package xflags
 
 import (
diff --git a/execute.go b/execute.go
index d39e3c766b57d214dce6cfd818414ae53a38dcbd..56ee244a2e0a57d0c88423a81176af11d73824ca 100644
--- a/execute.go
+++ b/execute.go
@@ -1,3 +1,7 @@
+// Copyright 2022 schukai GmbH. All rights reserved.
+// Use of this source code is governed by a AGPL-3.0
+// license that can be found in the LICENSE file.
+
 package xflags
 
 import (
diff --git a/execute_test.go b/execute_test.go
index 43335b8ff95a3cc010ae91d8f6b2094e214c3909..6444edea57cf64de9871cb76f968e6c59eab9c65 100644
--- a/execute_test.go
+++ b/execute_test.go
@@ -1,3 +1,7 @@
+// Copyright 2022 schukai GmbH. All rights reserved.
+// Use of this source code is governed by a AGPL-3.0
+// license that can be found in the LICENSE file.
+
 package xflags
 
 import (
diff --git a/flag.go b/flag.go
index 2f2d8b4186d52ab0474da6ec8dbf872b9e421956..122fbbad3984f1336a519546015ada2cd8e2d279 100644
--- a/flag.go
+++ b/flag.go
@@ -1,3 +1,7 @@
+// Copyright 2022 schukai GmbH. All rights reserved.
+// Use of this source code is governed by a AGPL-3.0
+// license that can be found in the LICENSE file.
+
 package xflags
 
 import (
diff --git a/flag_test.go b/flag_test.go
index 843e64b69110287d1644960e5f4fbc5d3de5132a..df67af092b4666e3c7fefa6fe2193243f7872f0d 100644
--- a/flag_test.go
+++ b/flag_test.go
@@ -1,3 +1,7 @@
+// Copyright 2022 schukai GmbH. All rights reserved.
+// Use of this source code is governed by a AGPL-3.0
+// license that can be found in the LICENSE file.
+
 package xflags
 
 import (
diff --git a/integration_test.go b/integration_test.go
index 3b076d9c01e237a5f5fff5487a5befec68048fc2..a8e778f51dc5f56cab5180dc7169f879521f035c 100644
--- a/integration_test.go
+++ b/integration_test.go
@@ -1,3 +1,7 @@
+// Copyright 2022 schukai GmbH. All rights reserved.
+// Use of this source code is governed by a AGPL-3.0
+// license that can be found in the LICENSE file.
+
 package xflags
 
 import (
diff --git a/parse.go b/parse.go
index 729f091bd2356f59d0061b8bb73c1649046fbb4b..c2eb85fb047481ce74f284119b18396d1684226e 100644
--- a/parse.go
+++ b/parse.go
@@ -1,3 +1,7 @@
+// Copyright 2022 schukai GmbH. All rights reserved.
+// Use of this source code is governed by a AGPL-3.0
+// license that can be found in the LICENSE file.
+
 package xflags
 
 import "os"
diff --git a/pathfind.go b/pathfind.go
index 643cdf720242a3aa295777e6b207d55da8493453..0ee103838105e374ca0874baf263b2e7a47f0d62 100644
--- a/pathfind.go
+++ b/pathfind.go
@@ -1,3 +1,7 @@
+// Copyright 2022 schukai GmbH. All rights reserved.
+// Use of this source code is governed by a AGPL-3.0
+// license that can be found in the LICENSE file.
+
 package xflags
 
 import (
diff --git a/pathfind_test.go b/pathfind_test.go
index 24eb42de6cb2f42d6e0dfab96eca9e4da9e7d6a5..696409e860c6b7f2fb1be37445e5d062f20c2b4a 100644
--- a/pathfind_test.go
+++ b/pathfind_test.go
@@ -1,3 +1,7 @@
+// Copyright 2022 schukai GmbH. All rights reserved.
+// Use of this source code is governed by a AGPL-3.0
+// license that can be found in the LICENSE file.
+
 package xflags
 
 import "testing"
diff --git a/readme_test.go b/readme_test.go
index 57e774bfce3e1970f3189f1ee299171a132e8672..5bbb4622e8fb197c45b09b16e70db675da1d6790 100644
--- a/readme_test.go
+++ b/readme_test.go
@@ -1,3 +1,7 @@
+// Copyright 2022 schukai GmbH. All rights reserved.
+// Use of this source code is governed by a AGPL-3.0
+// license that can be found in the LICENSE file.
+
 package xflags
 
 import (
diff --git a/setting.go b/setting.go
index a87a95466a2fb8653d64735111ae7a9824134104..2a4dd723ea3b08ffb0049f075c98616f5a32184e 100644
--- a/setting.go
+++ b/setting.go
@@ -1,3 +1,7 @@
+// Copyright 2022 schukai GmbH. All rights reserved.
+// Use of this source code is governed by a AGPL-3.0
+// license that can be found in the LICENSE file.
+
 package xflags
 
 import (
diff --git a/setting_test.go b/setting_test.go
index 9e7c7a58be5110a70d292d6ba9f4eea297d070fa..23a08b8cae0873905a792644c1e0b47afc74de9d 100644
--- a/setting_test.go
+++ b/setting_test.go
@@ -1,3 +1,7 @@
+// Copyright 2022 schukai GmbH. All rights reserved.
+// Use of this source code is governed by a AGPL-3.0
+// license that can be found in the LICENSE file.
+
 package xflags
 
 import (
diff --git a/shadow.go b/shadow.go
index 2aae3a8568703ae56448c4b4a64bbb52247b505b..7570d31905ce9f7a66a06de77fdd71a7b0f4f2ac 100644
--- a/shadow.go
+++ b/shadow.go
@@ -1,3 +1,7 @@
+// Copyright 2022 schukai GmbH. All rights reserved.
+// Use of this source code is governed by a AGPL-3.0
+// license that can be found in the LICENSE file.
+
 package xflags
 
 import "reflect"
diff --git a/shadow_test.go b/shadow_test.go
index debcc1b4e679179078ea054e35034cbcfda1b600..cc8b19ed85fdb0720dea1b7bcc8e1d57f6f5bc39 100644
--- a/shadow_test.go
+++ b/shadow_test.go
@@ -1,3 +1,7 @@
+// Copyright 2022 schukai GmbH. All rights reserved.
+// Use of this source code is governed by a AGPL-3.0
+// license that can be found in the LICENSE file.
+
 package xflags
 
 import (
diff --git a/tags.go b/tags.go
index dad791ceb7d2478edff5d40d234ce3fc5704519c..11ca988029adef3b3ed0774687f793a6f65b0e02 100644
--- a/tags.go
+++ b/tags.go
@@ -1,3 +1,7 @@
+// Copyright 2022 schukai GmbH. All rights reserved.
+// Use of this source code is governed by a AGPL-3.0
+// license that can be found in the LICENSE file.
+
 package xflags
 
 import (
diff --git a/tags_test.go b/tags_test.go
index eab10fb89d2ac54ba1999aa18de8fe4aae94e2c4..943d05396dc9326d567f776cf5df10e6ded10629 100644
--- a/tags_test.go
+++ b/tags_test.go
@@ -1,3 +1,7 @@
+// Copyright 2022 schukai GmbH. All rights reserved.
+// Use of this source code is governed by a AGPL-3.0
+// license that can be found in the LICENSE file.
+
 package xflags
 
 import (