Nevermind, it looks like it doesn't have any buffer space.
If it's a one off isn't this exactly what nohup is designed for?
This isn't a one-off; I want a simple solution that requires as little setup as possible. I also want infinite buffer space to store the stdout and stderr of processes, which neither screen nor tmux provide (both require you to preallocate buffer space).
Oh.
Well if it's a daemon type tool, write an init file - either a shell script for sysvinit or a service file for systemd.
Either write programs that daemonize themselves or write upstart/systemd services