Answer by wisbucky for Turning off auto indent when pasting text into vim

Native paste / bracketed paste is the best and simplest way since vim 8 (released in 2016). It even works over ssh! (Bracketed paste works on Linux and Mac, but not Windows Git Bash)

1. Make sure you have vim 8+ (you don't need the +clipboard or +xterm_clipboard options).

   vim --version | head -1

2. Simply use the OS native paste command (e.g. ctrl+shift+V or cmd+V) in Normal Mode. Do not press i for Insert Mode.

Test

1. Copy (ctrl+shift+C or cmd+C) the output of this (2 lines with a tab indent) to the system clipboard:

   echo -e '\ta\n\tb'

2. Launch a clean vim 8+ with autoindent:

   vim -u NONE --noplugin -c 'set autoindent'

3. Paste from the system clipboard (ctrl+shift+V or cmd+V) in Normal Mode. Do not press i for Insert Mode. The a and b should be aligned with a single tab indent. You can even do this while ssh-ing to a remote machine (the remote machine will need vim 8+).

4. Now try the old way, which will autoindent the second line with an extra tab: Press i for Insert Mode. Then paste using ctrl+shift+V or cmd+V. The a and b are misaligned now.

Installing Vim 8

• Ubuntu 18.04 - comes with Vim 8 by default.

• Ubuntu 16.04 - install from a PPA.

  sudo add-apt-repository ppa:jonathonf/vim
  sudo apt update
  sudo apt install vim
  

• Mac: brew install vim