Three tmux hooks make pane logging automatic instead of a keypress you forget

The part worth understanding here is why the author did not just patch the plugin.

tmux-logging pipes a pane through BSD sed. When sed's stdout points at a file, it is block-buffered, so an active log shows 0 bytes until the buffer fills or logging stops ^[5]. The comments in the script put the fill threshold at roughly 4 to 64KB ^[6]. For incident work, the pane you want to read is the pane that has not flushed yet. The replacement pipes through awk with an fflush() per line ^[7].

The front end lives at ~/.tmux/logging-live.sh, outside the plugin directory, so prefix U (tpm update) does not overwrite it ^[8]. It sources the plugin's own variables.sh to get $logging_full_filename, which keeps @logging-path and @logging-filename in .tmux.conf as the single source of truth ^[9]. Reading someone else's script for its variables is a coupling, not a clean interface, and the author says so plainly in the header comment.

The hooks pass the pane id explicitly: each set-hook runs the script with #{pane_id} expanded by tmux ^[2]. According to the script's comments, run-shell -t does not export TMUX_PANE, so without an explicit id every tmux call inside would resolve to whichever pane happens to be active ^[10]. For a hook firing on a newly created pane that is the right pane. For prefix P pressed while a background pane is the target, it is the wrong one ^[11].

Three hooks are claimed to cover every way a pane comes into existence: after-new-session, after-new-window, after-split-window ^[1][3]. The claim holds for the ordinary paths. The post does not say what happens with join-pane, break-pane or respawn-pane, and none of those fire the three hooks named here, so a pane that arrives by one of those routes is untested by this writeup.

Two adoption costs are in the config itself. tmux does not expand $HOME or ~ inside option values, so @logging-path has to be an absolute path with your username typed into it ^[4]. And the key binding has to come after the tpm run line, because tpm binds P itself ^[12]. A .tmux.conf that puts the bind-key first loses the toggle silently.

Existing panes are not adopted by the hooks. The post gives a one-time loop over tmux list-panes -a -F '#{pane_id}' to start each of them ^[13]. Everything created after the reload logs itself ^[14].

The environment is the limit on transferring any of this. It was written and tested on macOS with tmux 3.7c, BSD awk 20200816 and zsh ^[15]. The author writes that the awk is plain POSIX, "so it should carry to Linux, but I have not tested it there" ^[16]. GNU sed on Linux has different buffering behaviour from BSD sed, so the 0-byte symptom that motivated the rewrite is a macOS observation until someone reproduces it elsewhere. The filename template includes #{session_name}, #{window_name}, #{pane_index} and a strftime timestamp ^[17]. A directory of those files is greppable by session.