A quine in Erlang

quine0

#!/usr/bin/env escript
%%!
%-*-Mode:erlang;coding:utf-8;tab-width:4;c-basic-offset:4;indent-tabs-mode:()-*-
% ex: set ft=erlang fenc=utf-8 sts=4 ts=4 sw=4 et:

-mode(compile).

main(["-i" | _]) ->
    MagicNumber = 0,
    GenerationName = filename:basename(escript:script_name()),
    "quine" ++ GenerationIndexStr = GenerationName,
    io:format("Hi, my name is \"~s\" (generation ~s)~n"
              "my magic number is ~w!~n",
              [GenerationName,GenerationIndexStr,MagicNumber]),
    exit_code(0);
main([]) ->
    Path = filename:dirname(?FILE),
    "quine" ++ GenerationIndexStr = filename:basename(?FILE),
    NewGenerationIndex = erlang:list_to_integer(GenerationIndexStr) + 1,
    NewGenerationName = "quine" ++ erlang:integer_to_list(NewGenerationIndex),
    {ok, GenerationCurrent} = file:read_file(?FILE),
    S = erlang:integer_to_list(binary:decode_unsigned(
        crypto:strong_rand_bytes(2))),
    GenerationNew = re:replace(GenerationCurrent,
                               "MagicNumber = [0-9]+,",
                               "MagicNumber = " ++ S ++ ",",
                               [global, {return, binary}]),
    FilePath = filename:join(Path,NewGenerationName),
    ok = file:write_file(FilePath,GenerationNew),
    ok = file:change_mode(FilePath,8#00775),
    io:format("~s is born!~n", [NewGenerationName]),
    exit_code(0).

exit_code(ExitCode) ->
    erlang:halt(ExitCode, [{flush, true}]).