title: Copy from one register to another
body: <p>How to copy the contents of one register to another without pasting on clipboard? I'd yanked one text and it got yanked in the default <code>"</code> register. Now I want to copy another text without deleting/overwriting <code>"</code> register. So I want to move the contents of <code>"</code> register to say some <code>a</code> or <code>b</code> register so that I can copy the new text inside <code>"</code>. How to do this?</p>