Rename Iterm2 tab from within tmux

You can use the tmux option set-titles

In my .tmux.conf I have the following line:

set-option -g set-titles on

You will need to restart the tmux server (kill existing sessions) or re-source the file before the change in your config takes effect. You can also run this for an existing session with <prefix>:set-option set-titles on

I could not get the set-titles to work when using the tmux integration in iTerm2 (running with tmux -CC)

Instead this works just fine

function tabname {
  if [ -z $TMUX ] ; then
    printf "\e]1;$@\a"
  else
   tmux rename-window "$@"
  fi
}