Many of the commands in tmux deal with a target and source window/pane and I know sometimes you can supply things like 1:2 to specify pane 2 of window 1, however now I'm looking at more advanced usage, sessions now seem to fit in to this aswell.

I constantly forget the syntax and I can't find detailed information about it in the documentation.

Could anyone help shed some light?


your answer is hidden in an example inside a text about target-pane :

target-pane (or src-pane or dst-pane) may be a pane ID or takes a similar form to target-window but with the optional addition of a period followed by a pane index or pane ID, for example: ‘mysession:mywindow.1’. If the pane index is omitted, the currently active pane in the specified window is used. The following special tokens are available for the pane index:

You can test it by creating a background/daemonized tmux session named $SESSION like so :

tmux new-session -d -s $SESSION

you can monitor this session in another terminal by using :

tmux attach-session -t $SESSION

and then using this command from the "non tmux" terminal

tmux send-keys -t $SESSION:0.42

and then if the pane 42 doesnt exist, tmux will complain.

Now by using a test string, like so :

tmux send-keys -t $SESSION:0.42 "test" C-m

You can pinpoint the exact pane interactively if you don't know the exact pane number that you want.

On a side note, you can display pane numbers inside a tmux session by entering (listed in the key bindings session of the documentation you linked)

    C-b q           Briefly display pane indexes.
  • So when the OP says "1:2 to specify pane 2 of window 1", it's a misunderstanding, because 1:2 specifies window 2 of session 1. Pane 2 of window 1 (of current session) would be :1.2. Right? – Kamil Maciorowski Dec 28 '17 at 13:23
  • It looks like so, i can't confirm right now that the "current session" is implied by not using anything before :1.2, but if you take the good habit of giving all your sessions a name it definitely works as expected (and protects bad interactions between scripts that run tmux non-interactively, or at least unattended) – poncet_f Dec 29 '17 at 15:19

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