How to Increase the Scrollback Buffer in a Running Screen Session

How do I increase the scrollback buffer in a running screen session?

The man page explains that you can enter command line mode in a running session by typing Ctrl+A, :, then issuing the scrollback <num> command.

How do I increase the 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).

GNU screen: how to check current scrollback value?

As soon as you enter scrollback mode (CtrlA then Esc), you should see a status line like

Copy mode - Column 71 Line 25(+3000) (80,25)

The 3000 is the scrollback size. As long as you're in scrollback mode, you can use CtrlG to see a shorter version of that status line. If you're no longer at the bottom, the +3000 will be changed to show how far you've scrolled back. It tells how many lines are available above the currently displayed region, so +0 means you've scrolled back all the way.

Linux screen command scrollback one screen

Working as intended. The cursor starts out at the bottom of the current page; pressing Ctrl+B moves it up to the top of the page, plus one line (just as if you'd pressed ↑ 25 times, or however many rows are on your screen).

Copying the GNU screen scrollback buffer to a file (extended hardcopy)

To write the entire contents of the scrollback buffer to a file, type

Ctrl + A and :
to get to command mode, then

hardcopy -h <filename>

In older versions of screen, if you just do hardcopy -h, it just writes to the file -h. This was fixed in version 4.2.0, so hardcopy -h writes to hardcopy.N where N is the current window number.