How to use tmux

This note was created on 2019-12-22
This note was last edited on 2023-04-04

"tmux" is a terminal multiplexer. It lets you switch easily between several programs in one terminal, detach them (they keep running in the background) and reattach them to a different terminal. And do a lot more...
To work with tmux you should understand it's concepts (pane, window and session) and how shortcuts work.

=== How tmux shortcuts work ===
Most of tmux shortcuts consist of prefix and command keys. By default, prefix is "Ctrl-b" (shortened as "C-b" in future). Command key may be a letter (both upper- and lowercase) or a symbol.  
Unlike hotkeys in other apps, you don't need to keep the prefix key held down while pressing the command key. You press the prefix key, then the command key.

=== Panes ===
This is the main feature of tmux. When you need a terminal with several windows running different apps (for example: a server, git, and vim), you'd use a few panes.
- Split V: "C-b %"
- Split H: "C-b ""
- Navigating: "C-b <arrow>"
- Fullscreen: "C-b z"
- Resize: "C-b C-<arrow>"
- Close: "C-d" or the following command:
  $ exit

=== Windows ===
Windows in tmux is like a tabs. If you need new set of panes, you will create a new window.
- New window: "C-b c"
- Close window: "C-b &"
- Next window: "C-b n"
- Previous window: "C-b p"
- Window by number: "C-b <num>"
- Rename window: "C-b p"
- Rename current window: "C-b ,"

=== Sessions ===
tmux sessions are the interface for using tmux. When you starting a tmux, you staring a tmux session.
- Detach current session: "C-b d"
- Detach session from list: "C-b D"
- View sessions: "C-b s"
- Kill session in view mode: "x"
- List sessions:
  $ tmux ls

- Rename session:
  $ tmux rename-session -t 0 <name>

- Connect to session by number:
  $ tmux attach -t <num>

- Connect to session by name:
  $ tmux attach -s <name>

=== Other ===
- Show time: "C-b t"

=== Configuration ===
A user-specific configuration file should be located at "~/.tmux.conf", while a global configuration file should be located at "/etc/tmux.conf".
Here's some basic options, you'd probably use:
- Enable mouse in tmux:
  ~~~
  set -g mouse on
  ~~~

- Enable colors for Bash:
  ~~~
  set -g default-terminal "screen-256color"
  ~~~

- Add shortcut for reloading configuration file:
  ~~~
  bind r source-file ~/.tmux.conf \; display-message "Configiration file successfully reloaded!"
  ~~~

- Change default shell (to fish, for example):
  ~~~
  set -g default-command /usr/bin/fish
  set -g default-shell /usr/bin/fish
  ~~~

- Change prefix key from "Ctrl-b" to "Ctrl-a":
  ~~~
  unbind C-b
  set -g prefix C-a
  bind C-a send-prefix
  ~~~

=== Read more ===
There is more options and shortcuts. You can read more here: http://man.openbsd.org/OpenBSD-current/man1/tmux.1