How to increase scrollback buffer size in tmux?

The history limit is a pane attribute that is fixed at the time of pane creation and cannot be changed for existing panes. The value is taken from the history-limit session option (the default value is 2000).

To create a pane with a different value you will need to set the appropriate history-limit option before creating the pane.

To establish a different default, you can put a line like the following in your .tmux.conf file:

set-option -g history-limit 3000

Note: Be careful setting a very large default value, it can easily consume lots of RAM if you create many panes.

For a new pane (or the initial pane in a new window) in an existing session, you can set that session’s history-limit. You might use a command like this (from a shell):

tmux set-option history-limit 5000 \; new-window

For (the initial pane of the initial window in) a new session you will need to set the “global” history-limit before creating the session:

tmux set-option -g history-limit 5000 \; new-session

Note: If you do not re-set the history-limit value, then the new value will be also used for other panes/windows/sessions created in the future; there is currently no direct way to create a single new pane/window/session with its own specific limit without (at least temporarily) changing history-limit (though show-option (especially in 1.7 and later) can help with retrieving the current value so that you restore it later).

Open tmux configuration file with the following command:

vim ~/.tmux.conf

In the configuration file add the following line:

set -g history-limit 5000

Log out and log in again, start a new tmux windows and your limit is 5000 now.

This builds on ntc2 and Chris Johnsen's answer. I am using this whenever I want to create a new session with a custom history-limit. I wanted a way to create sessions with limited scrollback without permanently changing my history-limit for future sessions.

tmux set-option -g history-limit 100 \; new-session -s mysessionname \; set-option -g history-limit 2000

This works whether or not there are existing sessions. After setting history-limit for the new session it resets it back to the default which for me is 2000.

I created an executable bash script that makes this a little more useful. The 1st parameter passed to the script sets the history-limit for the new session and the 2nd parameter sets its session name:

#!/bin/bash
tmux set-option -g history-limit "${1}" \; new-session -s "${2}" \; set-option -g history-limit 2000