余談ですが mikutter の World の追加で認証エラーになると落ちますね……
/usr/pkg/lib/ruby/gems/2.4.0/gems/oauth-0.5.4/lib/oauth/consumer.rb:236:in `token_request': 401 Authorization Required
中略
notice: {MIKUTTER_DIR}/mikutter.rb:72:in `rescue in boot!': catch exception `SystemExit'
notice: {MIKUTTER_DIR}/mikutter.rb:74:in `rescue in boot!': => `SystemExit'
notice: {MIKUTTER_DIR}/mikutter.rb:106:in `rescue in <main>': catch SystemExit
notice: {MIKUTTER_DIR}/mikutter.rb:83:in `error_handling!': catch OAuth::Unauthorized