How to enter copy mode on mouse scroll in tmux

Ctrl-b then [ then you can use your normal navigation keys to scroll around (eg. Up Arrow or PgDn). Press q to quit scroll mode.

Alternatively you can press Ctrl-b PgUp to go directly into copy mode and scroll one page up (which is what it sounds like you will want most of the time)

In vi mode (see below), you can also scroll the page up/down line by line using Shift-k and Shift-j (if you're already in scroll mode). Unshifted, the cursor moves instead of the page.

Excerpts from the man page:

tmux may be controlled from an attached client by using a key combination of a prefix key, ‘C-b’ (Ctrl-b) by default, followed by a command key.

 The default command key bindings are:

[           Enter copy mode to copy text or view the history.

Function                     vi              emacs
--------                     --              -----
Half page down               C-d             M-Down
Half page up                 C-u             M-Up
Next page                    C-f             Page down
Previous page                C-b             Page up
Scroll down                  C-Down or C-e   C-Down
Scroll up                    C-Up or C-y     C-Up
Search again                 n               n
Search again in reverse      N               N
Search backward              ?               C-r
Search forward               /               C-s

Plus a bunch more. Note that you have to press C-b twice if you use that for page up since C-b is bound as the command key. See the man page for information on prefacing a copy mode command with a repeat count.

You can set the key binding mode using Ctrl-b, then

:set-window-option mode-keys emacs

or vi.

To scroll within history of the output You would use ^b + [ You can then use M+V to page up and ^V to page down. I don't know if You can use the real PgUp and PgDown though. My terminal does not send these keys to the tmux. Instead it scrolls itself and not the tmux history.

To exit the copy mode, press ESC

To use your mouse in this mode (called copy mode) press ^b + : and enter following:

setw -g mouse on

Note: In tmux < 2.1, the option was named mode-mouse, and not mouse

Now when You change to the copy mode you can use your mouse to scroll through it. You can put this command in your ~/.tmux.conf if You want so it loads every time You run tmux.

Update: As of tmux 1.5 this option makes using the scroll wheel automatically switch to copy mode and scroll back the tmux scrollback buffer. It is not necessary to first hit Ctrl-B + [ any more. Scrolling back down to the prompt also ends copy mode automatically.