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TMUX (Terminal Multiplexer)

(This section is meant as a quick reference rather than a full tutorial)

1. What is tmux

  • Normally, when we want to run programs, we use a terminal. If we want to run multiple programs, we open multiple terminal windows, and each one runs a separate program.

  • tmux (short for terminal multiplexer) is a tool that lets us run and manage multiple terminal sessions inside a single terminal window.

  • It allows us to organize our work into sessions, windows, and panes—all within one place.

2. Works like a background task

  • With a normal terminal, if a user logs out or closes the session, the terminal is closed and any running programs will stop.

  • However, tmux behaves differently. It keeps your sessions running in the background, even if you close the terminal or get disconnected.

  • We can later reconnect to the same session and continue your work exactly where you left off.

3. Quick Reference

Note: All shorthands start with Ctrl + b

tmux

tmux new -s mysession   (Start a named session)

tmux ls

tmux attach -t mysession    (Attach to a session)

Ctrl + b, then d    (Detach from a session)

Ctrl + b, then c    (Create a new window)

Ctrl + b, then n    (Switch to next window)

Ctrl + b, then p    (Switch to previous window)

Ctrl + b, then ,    (Rename a window)

Ctrl + b, then "    (Split pane horizontally)

Ctrl + b, then %    (Split pane vertically)

Ctrl + b, then arrow keys   (Move between panes)

exit    (Close a pane)

tmux kill-session -t mysession  (Kill a tmux session)

tmux kill-server    (Kill all servers)

4. Who is tmux useful for?

  • Developers: Running editors, servers, logs, and builds at the same time without opening many terminals.

  • System administrators / DevOps engineers: Managing remote servers over SSH, especially when connections may drop.

  • Anyone running long tasks: Like scripts, data processing, or training jobs that should keep running even if the terminal is closed.

  • People who prefer keyboard-driven workflows

  • tmux helps avoid constantly switching between multiple terminal windows.

5. Why not use backgorund tasks instead of tmux?

  • We start a process in the background; It keeps running after you close the terminal;

  • But we lose easy interaction with it

  • So, with background tasks, following are difficult:

    -see live output cleanly

    -interact with the program (menus, prompts, debugging)

    -manage multiple related processes together