robust tmux zoom toggle

.tmux.conf

# zoom
unbind ^M
bind ^M new-window -d -n zoom 'tmux-zoom'

tmux-zoom

#!/bin/bash

if [ -f /tmp/tmux-unzoom ];
then
  sh /tmp/tmux-unzoom
  tmux kill-window -t $TMUX_PANE
else
  # Don't zoom if there's only one pane
  if [ `tmux list-panes | wc -l` -le 1 ];
  then
    tmux kill-window -t $TMUX_PANE
    exit
  fi

  window=`tmux display-message -p "#I"`
  pane=`tmux display-message -p "#P"`

  tmux select-window -t $TMUX_PANE
  zoom_window=`tmux display-message -p "#I"`

  tmux swap-pane -s $window.$pane
  echo "rm /tmp/tmux-unzoom && tmux select-window -t $TMUX_PANE \; select-pane -t $TMUX_PANE \; swap-pane -s $zoom_window.1 \; kill-window -t $zoom_window" > /tmp/tmux-unzoom

  echo "Zoomed to window $zoom_window. Press enter to unzoom..."

  # Sometimes read fails, so loop until we get a good one
  while :
  do
    read 2> /dev/null
    if [ $? -eq 0 ]
    then
      break
    fi
  done

  sh /tmp/tmux-unzoom
fi