tmux

tmux is a terminal multiplexer for Unix-like systems. It enables multiple terminal sessions to be created, accessed, and controlled from a single window, with the ability to detach from a session and reattach later. tmux runs as a server, with a separate client communicating with it via a socket. It was designed as a modern alternative to GNU Screen and emphasizes flexibility, scripting, and a programmable interface. tmux is free and open source, released under a BSD-style license.

Core concepts include sessions, windows, and panes. A session contains one or more windows, each window contains one or more panes that divide the terminal area horizontally or vertically. A single tmux server can host multiple sessions; users can detach from a session on one terminal and reattach from another. The default command prefix is Ctrl-b, after which commands are typed or issued from a command prompt. Common operations include new-session, attach, detach, split-window -v or -h, resize-pane, select-pane, swap-pane, kill-pane, new-window, and rename-window.

tmux supports synchronized panes, copy mode for scrolling and selecting text, and a programmable status bar. Configuration is stored in ~/.tmux.conf and can customize key bindings, options, and start-up behavior. It integrates with plugins such as the tmux plugin manager (tpm) and collections offering session resurrection, status customization, and clipboard integration. tmux works over SSH and is compatible with most terminal emulators; clipboard integration depends on the system and terminal.

History: Created by Nicholas Marriott in 2007 as a replacement for GNU Screen; it has become widely adopted in development and operations workflows. It is available on many Unix-like systems and released under a permissive license. See also GNU Screen, Byobu, and terminal multiplexing concepts.