How to Copy and Paste with tmux on Mac OS X

Josh Clayton

Update (Jul1 19, 2013) - tmux 1.8 is out, and with it comes a simplified integration with the OS X clipboard. Check out tmux Copy and Paste on OS X: A Better Future for or updated technique.

tmux is becoming pretty popular as of late, but as with any new technology, there are skeptics. I’m here to quell some rumors and outline how to start using tmux effectively.

Out of all the questions I get, the most common is, “Does copying and pasting work in tmux? I heard it wasn’t possible.” Forget that noise; copying and pasting works wonderfully with a couple of extra steps.

Step 1: Install reattach-to-user-namespace

If you’re using Homebrew, run:

brew install reattach-to-user-namespace

If you’re not, head to the repository and follow the instructions to compile yourself. Be sure to check out Chris Johnsen’s great writeup about what reattach-to-user-namespace is actually doing.

Step 2: Configure tmux

Open up your tmux configuration (typically at ~/.tmux.conf) and throw this line at the top of the file:

set-option -g default-command "reattach-to-user-namespace -l zsh"

This assumes that you’ve installed reattach-to-user-namespace (and it’s in your $PATH) and that you’re using zsh. Every time you open a new window or pane, it’ll run reattach-to-user-namespace, which digs into some of Apple’s inner-workings to enable pbcopy and pbpaste support.

Step 3: Configure Other Applications

If you’re using Vim in a terminal, set your clipboard to the unnamed clipboard (make sure it’s not wrapped in a conditional has("gui_running")).

set clipboard=unnamed

If you want copying and pasting to work from your tmux buffers, you may want to run something similar to this:


while true; do
  if test -n "`tmux showb 2> /dev/null`"; then
    tmux saveb -|pbcopy && tmux deleteb
  sleep 0.5

That’ll look to see if there are any buffers in tmux; if there are, it’ll copy it into the system clipboard and delete the buffer. This is really handy if you’re trying to grab a backtrace or the output from a command.