diff --git a/erlang/Makefile b/erlang/Makefile
index 7db2c2b..ca8ed46 100644
--- a/erlang/Makefile
+++ b/erlang/Makefile
@@ -1,3 +1,21 @@
+# Makefile for pdp10-tools/erlang
+# Copyright (C) 2018  Mikael Pettersson
+#
+# This file is part of pdp10-tools.
+#
+# pdp10-tools is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# pdp10-tools is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with pdp10-tools.  If not, see <http://www.gnu.org/licenses/>.
+
 REBAR3=$(shell type -p rebar3 || echo ./rebar3)
 REBAR3_GIT=https://github.com/erlang/rebar3.git
 REBAR3_VSN=3.7.5
diff --git a/erlang/apps/8to9/src/8to9.app.src b/erlang/apps/8to9/src/8to9.app.src
index d7e9658..ed7eacd 100644
--- a/erlang/apps/8to9/src/8to9.app.src
+++ b/erlang/apps/8to9/src/8to9.app.src
@@ -1,3 +1,20 @@
+%%% Copyright (C) 2018  Mikael Pettersson
+%%%
+%%% This file is part of pdp10-tools.
+%%%
+%%% pdp10-tools is free software: you can redistribute it and/or modify
+%%% it under the terms of the GNU General Public License as published by
+%%% the Free Software Foundation, either version 3 of the License, or
+%%% (at your option) any later version.
+%%%
+%%% pdp10-tools is distributed in the hope that it will be useful,
+%%% but WITHOUT ANY WARRANTY; without even the implied warranty of
+%%% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+%%% GNU General Public License for more details.
+%%%
+%%% You should have received a copy of the GNU General Public License
+%%% along with pdp10-tools.  If not, see <http://www.gnu.org/licenses/>.
+
 {application, '8to9',
  [{description, "Converts octet files to nonet files"},
   {vsn, "0.1.0"},
diff --git a/erlang/apps/8to9/src/8to9.erl b/erlang/apps/8to9/src/8to9.erl
index 091352c..6fc3d69 100644
--- a/erlang/apps/8to9/src/8to9.erl
+++ b/erlang/apps/8to9/src/8to9.erl
@@ -1,22 +1,22 @@
 %%% -*- erlang-indent-level: 2 -*-
 %%%
+%%% 8to9 -- convert octet files to nonet files
 %%% Copyright (C) 2013-2018  Mikael Pettersson
 %%%
-%%% Licensed under the Apache License, Version 2.0 (the "License");
-%%% you may not use this file except in compliance with the License.
-%%% You may obtain a copy of the License at
+%%% This file is part of pdp10-tools.
 %%%
-%%%     http://www.apache.org/licenses/LICENSE-2.0
+%%% pdp10-tools is free software: you can redistribute it and/or modify
+%%% it under the terms of the GNU General Public License as published by
+%%% the Free Software Foundation, either version 3 of the License, or
+%%% (at your option) any later version.
 %%%
-%%% Unless required by applicable law or agreed to in writing, software
-%%% distributed under the License is distributed on an "AS IS" BASIS,
-%%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-%%% See the License for the specific language governing permissions and
-%%% limitations under the License.
+%%% pdp10-tools is distributed in the hope that it will be useful,
+%%% but WITHOUT ANY WARRANTY; without even the implied warranty of
+%%% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+%%% GNU General Public License for more details.
 %%%
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-%%%
-%%% Convert octet files to nonet files.
+%%% You should have received a copy of the GNU General Public License
+%%% along with pdp10-tools.  If not, see <http://www.gnu.org/licenses/>.
 
 -module('8to9').
 -export([main/1]).
diff --git a/erlang/apps/lib/src/escript_runtime.erl b/erlang/apps/lib/src/escript_runtime.erl
index 5b1c885..1bd5316 100644
--- a/erlang/apps/lib/src/escript_runtime.erl
+++ b/erlang/apps/lib/src/escript_runtime.erl
@@ -1,22 +1,22 @@
 %%% -*- erlang-indent-level: 2 -*-
 %%%
+%%% Runtime support for stand-alone programs started as escripts.
 %%% Copyright (C) 2018  Mikael Pettersson
 %%%
-%%% Licensed under the Apache License, Version 2.0 (the "License");
-%%% you may not use this file except in compliance with the License.
-%%% You may obtain a copy of the License at
+%%% This file is part of pdp10-tools.
 %%%
-%%%     http://www.apache.org/licenses/LICENSE-2.0
+%%% pdp10-tools is free software: you can redistribute it and/or modify
+%%% it under the terms of the GNU General Public License as published by
+%%% the Free Software Foundation, either version 3 of the License, or
+%%% (at your option) any later version.
 %%%
-%%% Unless required by applicable law or agreed to in writing, software
-%%% distributed under the License is distributed on an "AS IS" BASIS,
-%%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-%%% See the License for the specific language governing permissions and
-%%% limitations under the License.
+%%% pdp10-tools is distributed in the hope that it will be useful,
+%%% but WITHOUT ANY WARRANTY; without even the implied warranty of
+%%% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+%%% GNU General Public License for more details.
 %%%
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-%%%
-%%% Runtime support for stand-alone programs started as escripts.
+%%% You should have received a copy of the GNU General Public License
+%%% along with pdp10-tools.  If not, see <http://www.gnu.org/licenses/>.
 
 -module(escript_runtime).
 
diff --git a/erlang/apps/lib/src/getopt.erl b/erlang/apps/lib/src/getopt.erl
index bb53ce0..86c1553 100644
--- a/erlang/apps/lib/src/getopt.erl
+++ b/erlang/apps/lib/src/getopt.erl
@@ -1,22 +1,22 @@
 %%% -*- erlang-indent-level: 2 -*-
 %%%
+%%% getopt for Erlang programs
 %%% Copyright (C) 2018  Mikael Pettersson
 %%%
-%%% Licensed under the Apache License, Version 2.0 (the "License");
-%%% you may not use this file except in compliance with the License.
-%%% You may obtain a copy of the License at
+%%% This file is part of pdp10-tools.
 %%%
-%%%     http://www.apache.org/licenses/LICENSE-2.0
+%%% pdp10-tools is free software: you can redistribute it and/or modify
+%%% it under the terms of the GNU General Public License as published by
+%%% the Free Software Foundation, either version 3 of the License, or
+%%% (at your option) any later version.
 %%%
-%%% Unless required by applicable law or agreed to in writing, software
-%%% distributed under the License is distributed on an "AS IS" BASIS,
-%%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-%%% See the License for the specific language governing permissions and
-%%% limitations under the License.
+%%% pdp10-tools is distributed in the hope that it will be useful,
+%%% but WITHOUT ANY WARRANTY; without even the implied warranty of
+%%% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+%%% GNU General Public License for more details.
 %%%
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-%%%
-%%% getopt for Erlang programs
+%%% You should have received a copy of the GNU General Public License
+%%% along with pdp10-tools.  If not, see <http://www.gnu.org/licenses/>.
 
 -module(getopt).
 -export([parse/2, parse/3]).
diff --git a/erlang/apps/lib/src/lib.app.src b/erlang/apps/lib/src/lib.app.src
index 4997b4b..e616da0 100644
--- a/erlang/apps/lib/src/lib.app.src
+++ b/erlang/apps/lib/src/lib.app.src
@@ -1,3 +1,20 @@
+%%% Copyright (C) 2018  Mikael Pettersson
+%%%
+%%% This file is part of pdp10-tools.
+%%%
+%%% pdp10-tools is free software: you can redistribute it and/or modify
+%%% it under the terms of the GNU General Public License as published by
+%%% the Free Software Foundation, either version 3 of the License, or
+%%% (at your option) any later version.
+%%%
+%%% pdp10-tools is distributed in the hope that it will be useful,
+%%% but WITHOUT ANY WARRANTY; without even the implied warranty of
+%%% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+%%% GNU General Public License for more details.
+%%%
+%%% You should have received a copy of the GNU General Public License
+%%% along with pdp10-tools.  If not, see <http://www.gnu.org/licenses/>.
+
 {application, lib,
  [{description, "pdp10-tools support library"},
   {vsn, "0.1.0"},
diff --git a/erlang/apps/lib/src/pdp10_stdio.erl b/erlang/apps/lib/src/pdp10_stdio.erl
index f9e961e..737d80a 100644
--- a/erlang/apps/lib/src/pdp10_stdio.erl
+++ b/erlang/apps/lib/src/pdp10_stdio.erl
@@ -1,18 +1,22 @@
 %%% -*- erlang-indent-level: 2 -*-
 %%%
+%%% stdio() clone for I/O with 9-bit bytes
 %%% Copyright (C) 2013-2018  Mikael Pettersson
 %%%
-%%% Licensed under the Apache License, Version 2.0 (the "License");
-%%% you may not use this file except in compliance with the License.
-%%% You may obtain a copy of the License at
+%%% This file is part of pdp10-tools.
 %%%
-%%%     http://www.apache.org/licenses/LICENSE-2.0
+%%% pdp10-tools is free software: you can redistribute it and/or modify
+%%% it under the terms of the GNU General Public License as published by
+%%% the Free Software Foundation, either version 3 of the License, or
+%%% (at your option) any later version.
 %%%
-%%% Unless required by applicable law or agreed to in writing, software
-%%% distributed under the License is distributed on an "AS IS" BASIS,
-%%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-%%% See the License for the specific language governing permissions and
-%%% limitations under the License.
+%%% pdp10-tools is distributed in the hope that it will be useful,
+%%% but WITHOUT ANY WARRANTY; without even the implied warranty of
+%%% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+%%% GNU General Public License for more details.
+%%%
+%%% You should have received a copy of the GNU General Public License
+%%% along with pdp10-tools.  If not, see <http://www.gnu.org/licenses/>.
 %%%
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %%%
diff --git a/erlang/apps/lib/src/strtol.erl b/erlang/apps/lib/src/strtol.erl
index 6ab85a1..bd77dd5 100644
--- a/erlang/apps/lib/src/strtol.erl
+++ b/erlang/apps/lib/src/strtol.erl
@@ -1,18 +1,22 @@
 %%% -*- erlang-indent-level: 2 -*-
 %%%
+%%% strtol() clone for Erlang
 %%% Copyright (C) 2018  Mikael Pettersson
 %%%
-%%% Licensed under the Apache License, Version 2.0 (the "License");
-%%% you may not use this file except in compliance with the License.
-%%% You may obtain a copy of the License at
+%%% This file is part of pdp10-tools.
 %%%
-%%%     http://www.apache.org/licenses/LICENSE-2.0
+%%% pdp10-tools is free software: you can redistribute it and/or modify
+%%% it under the terms of the GNU General Public License as published by
+%%% the Free Software Foundation, either version 3 of the License, or
+%%% (at your option) any later version.
 %%%
-%%% Unless required by applicable law or agreed to in writing, software
-%%% distributed under the License is distributed on an "AS IS" BASIS,
-%%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-%%% See the License for the specific language governing permissions and
-%%% limitations under the License.
+%%% pdp10-tools is distributed in the hope that it will be useful,
+%%% but WITHOUT ANY WARRANTY; without even the implied warranty of
+%%% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+%%% GNU General Public License for more details.
+%%%
+%%% You should have received a copy of the GNU General Public License
+%%% along with pdp10-tools.  If not, see <http://www.gnu.org/licenses/>.
 %%%
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %%%
diff --git a/erlang/apps/od/src/od.app.src b/erlang/apps/od/src/od.app.src
index 1ad93dd..5a48f15 100644
--- a/erlang/apps/od/src/od.app.src
+++ b/erlang/apps/od/src/od.app.src
@@ -1,6 +1,23 @@
+%%% Copyright (C) 2018  Mikael Pettersson
+%%%
+%%% This file is part of pdp10-tools.
+%%%
+%%% pdp10-tools is free software: you can redistribute it and/or modify
+%%% it under the terms of the GNU General Public License as published by
+%%% the Free Software Foundation, either version 3 of the License, or
+%%% (at your option) any later version.
+%%%
+%%% pdp10-tools is distributed in the hope that it will be useful,
+%%% but WITHOUT ANY WARRANTY; without even the implied warranty of
+%%% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+%%% GNU General Public License for more details.
+%%%
+%%% You should have received a copy of the GNU General Public License
+%%% along with pdp10-tools.  If not, see <http://www.gnu.org/licenses/>.
+
 {application, od,
  [{description, "'od' clone for nonet files"},
-  {vsn, "0.1.0"},
+  {vsn, "0.3.0"},
   {registered, []},
   {applications, [kernel, stdlib, lib]},
   {env, []},
diff --git a/erlang/apps/od/src/od.erl b/erlang/apps/od/src/od.erl
index 8cb97e1..b92a51a 100644
--- a/erlang/apps/od/src/od.erl
+++ b/erlang/apps/od/src/od.erl
@@ -1,22 +1,22 @@
 %%% -*- erlang-indent-level: 2 -*-
 %%%
+%%% 'od' clone for files with 9-bit bytes
 %%% Copyright (C) 2013-2018  Mikael Pettersson
 %%%
-%%% Licensed under the Apache License, Version 2.0 (the "License");
-%%% you may not use this file except in compliance with the License.
-%%% You may obtain a copy of the License at
+%%% This file is part of pdp10-tools.
 %%%
-%%%     http://www.apache.org/licenses/LICENSE-2.0
+%%% pdp10-tools is free software: you can redistribute it and/or modify
+%%% it under the terms of the GNU General Public License as published by
+%%% the Free Software Foundation, either version 3 of the License, or
+%%% (at your option) any later version.
 %%%
-%%% Unless required by applicable law or agreed to in writing, software
-%%% distributed under the License is distributed on an "AS IS" BASIS,
-%%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-%%% See the License for the specific language governing permissions and
-%%% limitations under the License.
+%%% pdp10-tools is distributed in the hope that it will be useful,
+%%% but WITHOUT ANY WARRANTY; without even the implied warranty of
+%%% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+%%% GNU General Public License for more details.
 %%%
-%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-%%%
-%%% 'od' clone for files with 9-bit bytes
+%%% You should have received a copy of the GNU General Public License
+%%% along with pdp10-tools.  If not, see <http://www.gnu.org/licenses/>.
 
 -module(od).
 -export([main/1]).
diff --git a/erlang/rebar.config b/erlang/rebar.config
index 1b66dc0..5f271ed 100644
--- a/erlang/rebar.config
+++ b/erlang/rebar.config
@@ -1,4 +1,22 @@
 %% -*- erlang -*-
+%% rebar.config for pdp10-tools
+%% Copyright (C) 2018  Mikael Pettersson
+%%
+%% This file is part of pdp10-tools.
+%%
+%% pdp10-tools is free software: you can redistribute it and/or modify
+%% it under the terms of the GNU General Public License as published by
+%% the Free Software Foundation, either version 3 of the License, or
+%% (at your option) any later version.
+%%
+%% pdp10-tools is distributed in the hope that it will be useful,
+%% but WITHOUT ANY WARRANTY; without even the implied warranty of
+%% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+%% GNU General Public License for more details.
+%%
+%% You should have received a copy of the GNU General Public License
+%% along with pdp10-tools.  If not, see <http://www.gnu.org/licenses/>.
+
 {eunit_opts, [verbose, {report, {eunit_surefire, [{dir, "."}]}}]}.
 
 {erl_opts, [ debug_info