Oh shoot! I started this process outside of tmux, but now I need to go away and it's been running a while, what can I do?
[Ctrl-z] on the process
bg
echo $! # get the PID (1608)
disown
tmux
reptyr 1608
@climagic One thing to be aware of: It sometimes only works once for a process. I tend to grab it while in screen/tmux for that reason.