tmux is a terminal multiplexer - it lets you work in multiple terminal (pseudo-)windows, inside the same terminal session.

It also lets you run a process in the background, and then reattach to it later.

Basic terminology and setup

  • The prefix key is the key combination that is always given before issuing a command in tmux. Usually the prefix key is Ctrl+b
  • Session is a single collection of terminals under the management of tmux.
  • A pane is the individual split terminal that you see on one screen.
  • A window in tmux is basically a tab, or a collection of panes.

To find out what the prefix-key is set as:

tmux list-keys

# or, within a tmux session, type (prefix-key) + ? to see key configurations

Quit a terminal session within Tmux:


Run a process and keep it running once logged off

If you want to run a long-running program, and keep it running after you log off, you can use tmux to do this.

tmux new -s my-long-process

This will create a new session called my-long-process, and you can then run your long-running process within that session.

To detach from the session, and leave it running in the background:

Ctrl+b, d

To reattach to the session:

tmux list-sessions

tmux attach -t my-long-process


Launch tmux:


Get help within tmux (quick keyboard shortcut reference):

Ctrl+b, ?
then 'q' to exit the help screen

Creating new panes

Create a new horizontal pane (split into two, left and right):

Ctrl+b, %

Create a vertical pane (split into two, top and bottom):

Ctrl+b, "

Working with panes

Resize a pane taller or shorter:

Ctrl+b, Ctrl+(Up or Down key)

Scroll within a pane:

Ctrl+b, [, then Up or Down.

To scroll back within a pane

If you want to see the previous buffer within a pane, you can enter copy mode which basically lets you scroll back through the buffer:

Ctrl+b, Page Up

You’ll also see a label at the top right, showing your position within the buffer, e.g. [29/1910]

Press q to exit copy mode.