def register(keyword, command)
      @aliases.register(keyword.to_sym) do
        lambda do |args|
          # directly execute shell commands
          if command.start_with?("!")
            return Util::SafeExec.exec "#{command[1..-1]} #{args.join(" ")}".strip
          end

          return CLI.new(command.split.concat(args), @env).execute
        end
      end
    end
def register(keyword, command)
      @aliases.register(keyword.to_sym) do
        lambda do |args|
          # directly execute shell commands
          if command.start_with?("!")
            return Util::SafeExec.exec "#{command[1..-1]} #{args.join(" ")}".strip
          end

          return CLI.new(command.split.concat(args), @env).execute
        end
      end
    end
This registers an alias.