tmux Command in Linux: Sessions, Panes, Windows & Key Bindings

Start work on a remote host without tying it to your current SSH window. A detached session keeps running after you log out.

Run the command:

tmux new -d -s work
tmux ls

Sample output:

work: 1 windows (created Wed Jul  1 14:18:30 2026)

The session name (work) is what you pass to tmux attach -t work when you reconnect.

After SSH drops or you detached with Ctrl+b d, attach to pick up where you left off.

Run the command:

tmux attach -t work

Sample output (when run from a real terminal):

[exits into the tmux session — status bar shows session name and window list]

If no session exists, tmux prints can't find session: work. Create it first with tmux new -s work or check names with tmux ls.

You can split panes with key bindings inside tmux, or drive layout from scripts using split-window.

Run the commands:

tmux new -d -s demo -n shell 'sleep 600'
tmux split-window -t demo:shell -h
tmux split-window -t demo:shell.1 -v
tmux list-panes -t demo:shell -F '#{pane_index} #{pane_width}x#{pane_height}'

Sample output:

0 40x24
1 39x12
2 39x11

Pane 0 is on the left; panes 1 and 2 stack on the right. Sessions started with 'sleep 600' exist only until sleep ends or you kill the session. Clean up with tmux kill-session -t demo when finished.

Windows are full-screen tabs inside one session — useful when one tab runs an app and another tails logs.

Run the commands:

tmux new -d -s ops -n app 'sleep 600'
tmux new-window -t ops -n logs 'sleep 600'
tmux list-windows -t ops
tmux display-message -t ops -p '#{session_name} #{window_name} #{window_index}'

Sample output:

0: app- (1 panes) [80x24] [layout b25d,80x24,0,0,0] @0
1: logs* (1 panes) [80x24] [layout b260,80x24,0,0,1] @1 (active)
ops logs 1

The * marks the active window. Switch inside tmux with Ctrl+b n, Ctrl+b p, or Ctrl+b 0–9.

Read what is visible in a pane without attaching interactively — handy for cron jobs or health checks.

Run the commands:

tmux new -d -s captest 'echo hello-from-tmux; sleep 30'
sleep 0.5
tmux capture-pane -t captest -p
tmux kill-session -t captest

Sample output:

hello-from-tmux

If the pane is empty, the session may have exited before capture — use exec sleep or a longer-running command in the pane.

send-keys injects keystrokes into the pane's current program state — it is not the same as running a shell command through a clean non-interactive shell.

Run the commands:

tmux new -d -s remote -n shell
tmux send-keys -t remote:shell 'top' Enter
tmux list-panes -t remote:shell
tmux kill-session -t remote

Sample output:

0: [80x24] [history 0/2000, 960 bytes] %0 (active)

Attach with tmux attach -t remote to see top running. Replace top with any command your workflow needs.

Automation and monitoring scripts can query tmux without parsing tmux ls text.

Run the command:

tmux new -d -P -F 'session=#{session_name} windows=#{session_windows}' -s formatted 'sleep 30'
tmux kill-session -t formatted

Sample output:

session=formatted windows=1

Use man tmux FORMATS section for placeholders like #{pane_id}, #{window_name}, and #{session_attached}.

A typical mistake after reboot or typo in the session name.

Run the command:

tmux attach -t nosuch

Sample output:

can't find session: nosuch

Run tmux ls to see valid names. If the list is empty, the server has no sessions — start a new one with tmux new -s NAME.

Isolate sessions (for example per project or per user script) with a named socket instead of the default default server.

Run the commands:

tmux -L dev new -d -s backend 'sleep 600'
tmux -L dev ls
tmux -L dev kill-server

Sample output:

backend: 1 windows (created Wed Jul  1 14:16:50 2026)

kill-server stops the named server. After killing the only session, the server normally exits automatically — kill-session -t backend alone is enough when no other sessions remain. Always pass the same -L dev flag to attach, list, or kill — otherwise you are talking to a different server.

After editing bindings or colours, reload the config from inside tmux or from the shell.

Run the command (from the shell while sessions run):

tmux source-file ~/.tmux.conf

Sample output:

No output usually means success. Errors are reported to the invoking tmux client. Check man tmux on your host for whether your version supports source-file -n (parse-only validation) or source-file -v (verbose parsed output). Startup config errors can also appear in the first session's pane when the server processes its initial configuration files.

Inside tmux you can also press Ctrl+b : then type source-file ~/.tmux.conf.