Tmux — Terminal Multiplexer Cheat Sheet

Prefix Key

Every tmux command is prefixed by the prefix key (default: Ctrl-b). Release Ctrl-b before pressing the command key.

Ctrl-b  →  then press command

To change prefix to Ctrl-a (like GNU Screen), add to ~/.tmux.conf:

set -g prefix C-a
unbind C-b
bind C-a send-prefix

Session Management

Sessions contain one or more windows. Use sessions for separate projects or contexts.

Command	Action
`tmux new -s <name>`	Create new named session
`tmux ls`	List all sessions
`tmux attach -t <name>`	Attach to existing session
`tmux kill-session -t <name>`	Kill a session
`tmux rename-session -t <old> <new>`	Rename session
`tmux switch -t <name>`	Switch to another session
`tmux new -s <name> -d`	Create session in background (detached)

Inside tmux:

Command	Action
`Ctrl-b s`	Interactive session list (arrow keys to select)
`Ctrl-b $`	Rename current session
`Ctrl-b d`	Detach current session (runs in background)
`Ctrl-b (` / `Ctrl-b )`	Switch to previous / next session

Window Management

Windows are tabs within a session.

Command	Action
`Ctrl-b c`	Create new window
`Ctrl-b ,`	Rename current window
`Ctrl-b &`	Kill current window (confirm)
`Ctrl-b n`	Next window
`Ctrl-b p`	Previous window
`Ctrl-b 0-9`	Switch to window by number
`Ctrl-b w`	Interactive window list
`Ctrl-b f`	Find window by name (search)
`Ctrl-b .`	Move window (prompt for index number)
`Ctrl-b l`	Toggle to last (previously active) window

Pane Management

Panes split a window into regions.

Creating Panes

Command	Action
`Ctrl-b "`	Split horizontally (top/bottom)
`Ctrl-b %`	Split vertically (left/right)

Navigating Panes

Command	Action
`Ctrl-b ←↑↓→` (arrow keys)	Move to pane in direction
`Ctrl-b q`	Show pane numbers (press number to jump)
`Ctrl-b o`	Cycle through panes
`Ctrl-b ;`	Toggle to last active pane

Resizing Panes

Command	Action
`Ctrl-b Ctrl-←↑↓→`	Resize pane 1 cell at a time
`Ctrl-b M-←↑↓→` (Alt+arrow)	Resize pane 5 cells at a time

Or enter resize mode with Ctrl-b :resize-pane:

# In tmux command mode (:)
resize-pane -D 20    # resize down 20 cells
resize-pane -U 10    # resize up 10 cells
resize-pane -L 15    # resize left 15 cells
resize-pane -R 25    # resize right 25 cells

Pane Layouts

Command	Action
`Ctrl-b space`	Cycle through preset layouts
`Ctrl-b M-1` to `M-5`	Set layout: even-horizontal, even-vertical, main-horizontal, main-vertical, tiled
`Ctrl-b z`	Zoom pane (toggle fullscreen for current pane)
`Ctrl-b !`	Break pane into a new window
`Ctrl-b x`	Kill current pane (confirm)
`Ctrl-b {` / `Ctrl-b }`	Swap pane left / right (or up / down)
`Ctrl-b q`	Show pane numbers briefly

Synchronizing Panes

Send the same keyboard input to all panes in the same window:

set -g synchronize-panes on   # enable (or from :prompt)
set -g synchronize-panes off  # disable

Toggle with: Ctrl-b : then set synchronize-panes

Copy Mode & Scrolling

Tmux has its own scrollback buffer. Mouse scroll wheel scrolls the buffer only if the mouse mode is on.

Entering / Exiting Copy Mode

Command	Action
`Ctrl-b [`	Enter copy (scrollback) mode
`Ctrl-b ]`	Paste from tmux buffer
`q` or `Enter`	Exit copy mode

Key	Action
`↑` / `↓`	Scroll line by line
`Ctrl-u` / `Ctrl-d`	Half page up / down
`Ctrl-b` / `Ctrl-f`	Full page up / down
`g` / `G`	Go to top / bottom of buffer
`h` / `l`	Move left / right character
`j` / `k`	Move down / up line
`w` / `b`	Jump word forward / backward
`0` / `$`	Jump to start / end of line

Copying in Copy Mode (vi keys)

Command	Action
`v`	Start selection (character mode)
`V`	Start selection (line mode)
`Ctrl-v`	Start selection (block mode)
`y`	Yank (copy) selection to tmux buffer
`Enter`	Copy selection and exit copy mode

Using mouse: Enable mouse support, then drag to select and release to copy.

Buffers (Clipboard)

Command	Action
`Ctrl-b =`	List / choose from paste buffers
`Ctrl-b ]`	Paste most recent buffer
`tmux save-buffer -b <name>`	Save buffer to file
`tmux set-buffer -b <name>`	Load text into buffer

Mouse Support

Enable mouse mode (recommended for beginners):

set -g mouse on

Once enabled: - Click panes / window tabs to switch - Scroll with mouse wheel to browse scrollback - Drag pane borders to resize - Drag & select text to copy to system clipboard (hold Shift on some terminals to bypass tmux)

Command Mode

Press Ctrl-b : to enter the tmux command prompt. Then type any of these:

Command	Action
`set -g <option> <value>`	Set global option
`setw -g <option> <value>`	Set window option
`display-message "text"`	Show message in status bar
`show-options -g`	List all global options
`show-window-options -g`	List all window options
`kill-session`	Kill current session
`new-window`	Create new window
`rename-window <name>`	Rename current window
`split-window -h`	Split horizontally
`split-window -v`	Split vertically
`list-keys`	Show all keybindings
`source-file ~/.tmux.conf`	Reload config (apply changes)

Status Bar Configuration

Set in ~/.tmux.conf:

# Status bar colors
set -g status-bg colour235
set -g status-fg colour255

# Left side: session name
set -g status-left '#[fg=green]#S '
set -g status-left-length 40

# Right side: date/time
set -g status-right '#[fg=yellow]%Y-%m-%d %H:%M'

# Center: window list
set -g status-justify centre

# Interval (seconds) to update status bar
set -g status-interval 5

# Refresh client automatically
set -g set-titles on

Essential `~/.tmux.conf` Snippets

256 Colors & True Color

set -g default-terminal "tmux-256color"
set -ga terminal-overrides ",xterm-256color:Tc"

Vi-style Copy Mode Keys

set -g mode-keys vi
set -g status-keys vi

Start Window Numbering at 1

set -g base-index 1
setw -g pane-base-index 1

Rebind Reload to `Ctrl-b r`

bind r source-file ~/.tmux.conf \; display-message "Config reloaded"

Increase Scrollback History

set -g history-limit 50000

Easy Pane Splitting (no prefix needed for alt keys — vim-like)

bind | split-window -h
bind - split-window -v

Smart Pane Resizing (hold prefix + H/J/K/L)

bind -r H resize-pane -L 5
bind -r J resize-pane -D 5
bind -r K resize-pane -U 5
bind -r L resize-pane -R 5

Quick Reference Card

┌─────────────────────────────────────────────────┐
│  tmux Quick Reference                            │
├─────────────────────────────────────────────────┤
│  Ctrl-b c   new window          Ctrl-b d   detach│
│  Ctrl-b ,   rename window       Ctrl-b s   session│
│  Ctrl-b n/p next/prev window    Ctrl-b $   rename│
│  Ctrl-b "   split horiz.        Ctrl-b %   vert. │
│  Ctrl-b ←→  pane navigation     Ctrl-b z   zoom │
│  Ctrl-b [   copy mode           Ctrl-b ]   paste│
│  Ctrl-b :   command prompt      Ctrl-b ?   keys │
└─────────────────────────────────────────────────┘

Troubleshooting

Problem	Fix
Tmux not found	`sudo apt install tmux` (Debian/Ubuntu), `brew install tmux` (macOS), `sudo dnf install tmux` (Fedora)
Colors look wrong	Set `default-terminal "tmux-256color"` and `TERM=xterm-256color` outside tmux
Can't scroll with mouse	Enable `set -g mouse on` in config
Scrollback too small	Increase `history-limit` (set before creating sessions)
Copy-paste not working with system clipboard	Install `xclip` or `xsel` on Linux, then add: `set -g set-clipboard on`
Config not applying	Run `tmux source-file ~/.tmux.conf` or `Ctrl-b :source-file ~/.tmux.conf`