/user/kayd @ devops :~$ cat tmux.md

tmux Cheatsheet tmux Cheatsheet

Karandeep Singh

Jul 2, 2025 • 6 minutes

Summary

My tmux notes. Session management, window and pane keybindings, copy mode, config essentials, and scripting layouts with send-keys.

Half my job happens inside tmux: long-running deploys that survive dropped SSH connections, split panes tailing logs on three servers at once, a scripted dev layout that comes up with one command. These are the commands and keybindings I actually use, nothing more. Pair it with my Bash CLI One-Liners Cheatsheet for what to run inside those panes.

All keybindings below assume the default prefix Ctrl-b (written C-b). Press the prefix, release, then press the key.

sessions › windows › panes

Three levels, and almost every tmux confusion is mixing them up. The session is the thing that survives — it lives on the server, so closing your laptop or dropping SSH detaches you without killing anything. Windows are tabs inside it; panes are splits inside a window.

Sessions

tmux new -s deploy            # new named session
tmux new -s deploy -d         # new session, detached (great in scripts)
tmux ls                       # list sessions
tmux attach -t deploy         # attach to a session by name
tmux attach -d -t deploy      # attach and detach any other client
tmux kill-session -t deploy   # kill one session
tmux kill-server              # kill everything
tmux rename-session -t 0 work # rename a session

Keybinding	Action
`C-b d`	Detach from session (it keeps running)
`C-b s`	Interactive session picker
`C-b $`	Rename current session
`C-b (` / `C-b )`	Previous / next session

The whole point: detach with C-b d, close your laptop, SSH back in later, tmux attach -t deploy, and your job is still running.

Windows

Windows are like tabs inside a session.

Keybinding	Action
`C-b c`	Create new window
`C-b ,`	Rename current window
`C-b n`	Next window
`C-b p`	Previous window
`C-b 0-9`	Jump to window by number
`C-b w`	Interactive window picker
`C-b &`	Kill current window (confirms)
`C-b .`	Move window to a new index
`C-b f`	Find window by name

Panes

Panes split a window into multiple terminals.

Keybinding	Action
`C-b %`	Split vertically (side by side)
`C-b "`	Split horizontally (stacked)
`C-b o`	Cycle to next pane
`C-b ;`	Toggle to last-active pane
`C-b arrows`	Move to pane in that direction
`C-b z`	Zoom pane fullscreen (toggle)
`C-b x`	Kill current pane (confirms)
`C-b {` / `C-b }`	Swap pane left / right
`C-b !`	Break pane out into its own window
`C-b q`	Show pane numbers (press number to jump)
`C-b Space`	Cycle through preset layouts

C-b z is the one to memorize. Zoom a pane to read logs full-screen, hit it again to drop back to the split.

Resizing & Layouts

Keybinding	Action
`C-b C-arrows`	Resize pane by 1 cell (hold prefix, tap arrow)
`C-b M-arrows`	Resize pane by 5 cells
`C-b M-1` … `M-5`	Apply preset layout (even-horizontal, even-vertical, main-horizontal, main-vertical, tiled)

tmux resize-pane -D 10        # resize down 10 cells (also -U, -L, -R)
tmux select-layout tiled      # apply a layout from the command line

Copy Mode & Scrollback

Keybinding	Action
`C-b [`	Enter copy mode (scrollback)
`q`	Exit copy mode
`C-b ]`	Paste most recent buffer
`C-b PgUp`	Enter copy mode scrolled up one page

With vi keys enabled (see config below), inside copy mode:

Key	Action
`k` / `j`, `C-u` / `C-d`	Scroll up / down, half-page up / down
`g` / `G`	Top / bottom of scrollback
`/` then text	Search down (`?` searches up)
`n` / `N`	Next / previous search match
`Space`	Start selection
`Enter` (or `y`)	Copy selection and exit

tmux show-buffer              # print last copied buffer
tmux list-buffers             # all paste buffers
tmux save-buffer /tmp/out.txt # dump buffer to a file

Synchronize Panes

Type into every pane in the window at once. Handy when you have a handful of servers open in splits and want to run the same command on all of them.

# toggle on/off (prompt shows "synchronize-panes on")
C-b : setw synchronize-panes

warning

Turn synchronize-panes off before doing anything destructive. It is easy to forget it is on and send sudo systemctl restart to four production hosts instead of one. Put the sync state in your status line so it is always visible.

~/.tmux.conf Essentials

# Remap prefix from C-b to C-a (easier to reach)
unbind C-b
set -g prefix C-a
bind C-a send-prefix

# Mouse support: click panes, drag borders, wheel scroll
set -g mouse on

# Start windows and panes at 1, not 0
set -g base-index 1
setw -g pane-base-index 1

# vi keys in copy mode
setw -g mode-keys vi
bind -T copy-mode-vi v send -X begin-selection
bind -T copy-mode-vi y send -X copy-selection-and-cancel

# Bigger scrollback, faster escape, sane colors
set -g history-limit 50000
set -sg escape-time 10
set -g default-terminal "tmux-256color"

# Renumber windows when one closes
set -g renumber-windows on

# Intuitive split keys that keep the current path
bind | split-window -h -c "#{pane_current_path}"
bind - split-window -v -c "#{pane_current_path}"

# Status line: session name, window list, host + time
set -g status-style bg=black,fg=green
set -g status-left "[#S] "
set -g status-right "#h %H:%M"

Reload without restarting:

tmux source-file ~/.tmux.conf     # or: C-b : source-file ~/.tmux.conf

Scripting tmux

send-keys and split-window let you build a whole dev environment in one script:

#!/usr/bin/env bash
SESSION="dev"

tmux new-session -d -s "$SESSION" -n editor
tmux send-keys -t "$SESSION:editor" 'cd ~/project && vim .' C-m

tmux split-window -h -t "$SESSION:editor"
tmux send-keys -t "$SESSION:editor.1" 'cd ~/project && hugo server -D' C-m

tmux new-window -t "$SESSION" -n logs
tmux send-keys -t "$SESSION:logs" 'journalctl -f' C-m

tmux select-window -t "$SESSION:editor"
tmux attach -t "$SESSION"

Notes: C-m is Enter; targets are session:window.pane; new-session -d means the script works even when run outside tmux. Idempotent version: tmux has-session -t dev 2>/dev/null || ./dev-env.sh.

Nested tmux (SSH Into a Server Running tmux)

When you run tmux locally and attach to a remote tmux over SSH, press the prefix twice to send it to the inner session: C-b C-b c creates a window on the remote. If you nest often, set the remote prefix to something else (e.g. C-a) so the two never collide.

Most-Used Commands

Command	What it does
`tmux new -s name`	New named session
`tmux ls`	List sessions
`tmux attach -t name`	Attach to session
`tmux kill-session -t name`	Kill session
`C-b d`	Detach
`C-b c` / `C-b n` / `C-b p`	New / next / previous window
`C-b %` / `C-b "`	Vertical / horizontal split
`C-b z`	Zoom pane
`C-b [`	Copy mode / scrollback
`C-b : setw synchronize-panes`	Type into all panes

Most of this pays off on remote boxes. See my Ubuntu Terminal Cheatsheet for the server-side commands you’ll be running inside those sessions.

Bash CLI One-Liners: the find/grep/jq/rsync pipelines I end up typing inside these panes
Ubuntu Terminal: apt, systemd, and journalctl on the servers these sessions are attached to
Amazon Linux 2 Terminal: the same idea for EC2, with yum, extras repos, SSM sessions, and instance-metadata queries

The rest of my terminal notes live in the Terminal group, and everything else is in the cheatsheet library.

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Sessions

Windows

Panes

Resizing & Layouts

Copy Mode & Scrollback

Synchronize Panes

~/.tmux.conf Essentials

Scripting tmux

Nested tmux (SSH Into a Server Running tmux)

Most-Used Commands

Related Cheatsheets

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