title: How to remove all special characters in Linux text
body: <p><a href="https://i.stack.imgur.com/gv4Dd.png" rel="noreferrer"><img src="https://i.stack.imgur.com/gv4Dd.png" alt="vim pic"></a>
  How to remove the special characters shown as blue color in the picture <a href="https://i.stack.imgur.com/gv4Dd.png" rel="noreferrer">1</a> like: ^M, ^A, ^@, ^[. In my understanding, ^M is a windows newline character, I can use <code>sed -i '/^M//g'</code> to remove it, but it doesn't work to remove others. The command <code>dos2unix</code> doesn't work, neither. Are there exist any ways that I can use to remove them both?</p>