How to copy long text from PuTTY to text document in Windows?

What I usually do:

  • Clear Scrollback (in PuTTY window title bar context [right-click] menu)
  • Reset Terminal (or clear command or equivalent)
  • display file, e.g.

    cat myfile
    
  • Copy All to Clipboard

You will obviously still get at least the cat myfile command in the clipboard, but you can easily remove that after pasting.