Question: Usually `tmux` will only show as much output as however many rows my terminal currently displays. And then when I detach it, it clears all of its content. I know how to look at scrollback (`ctrl+A`, `[`, `k`, ...), but how can I configure tmux to just print all its output to terminal, as if I wasn't using it at all?

I like `tmux` because I'm awful at remembering to `nohup` certain tasks, and because it makes viewing the output of long-running jobs easier. But I would like to be able to view its scrollback more naturally, by simply *scrolling back* in iTerm2.

Alternatively, if there's a way to do this in `screen`, I can use that too.

Answer: 
Add this to your `~/.tmux.conf` and you will be able to enter copy mode just by scrolling:

```
setw -g mode-mouse on

```

You may also want to enable other mouse features:

```
set -g mouse-resize-pane on
set -g mouse-select-pane on
set -g mouse-select-window on

```

See this excellent write-up of these features: <http://tangledhelix.com/blog/2012/07/16/tmux-and-mouse-mode/>
In my case, just putting `set-option -g status off` in `.tmux.conf` allows to leave the scrollback in the terminal. But you lose the status bar.