Executes a command after adding a `.env` file to the environment. This is probably terribly unsafe.

dotenv.rb

#!/usr/bin/env ruby

# usage: dotenv irb

begin
  File.foreach('.env') do |line|
    line = line.strip
    unless line.start_with?('#')
      parts = line.split '=', 2
      if parts.length == 2
        ENV[parts[0]] = parts[1]
      end
    end
  end
rescue Exception => err
  STDERR.puts err
end

exec(*ARGF.argv)