Help interpreting this sentence


I have trouble understanding the sentence below

文章が長くならないよう、必要のない部分は省略した

I roughly translate: literature doesn't need to be long, omit unnecessary part

  * Can I use passive form “unnecessary part was omitted” instead?
  * How should I interpret ならないよう、必要のない部分. I don’t understand why のis there




  * `dictionary-form + よう` means "so as to ～", "so that ～", etc. See [this article](http://japanesetest4you.com/flashcard/learn-jlpt-n3-grammar-%E3%82%88%E3%81%86%E3%81%AB-you-ni/).
  * 必要のない部分 literally means "the part where there is not necessity". 必要のない is a relative clause that adjectivally modifies 部分, and の can be used in place of が in relative clauses. See: [How does the の work in 「日本人の知らない日本語」?](https://japanese.stackexchange.com/q/12825/5010) Of course you can simply translate it as "unnecessary parts".
  * した is not an imperative form. This sentence is not an order but a neutral sentence with the omitted subject (="I"). The last half literally means " _I_ omitted unnecessarily parts", but you can translate it also as "unnecessary parts were omitted".

