Set OPTION for all windows
misc
// what it does
`setw -g OPTION` (short for `set-window-option -g`) sets a window option in the global window table, applying it to all windows across all sessions. Reach for it when configuring per-window behavior such as `mode-keys vi`, `automatic-rename off`, or `monitor-activity on`. Modern tmux has merged the option tables, so plain `set -g` works too, but `setw` remains the explicit, unambiguous form.
// tmux command
: setw -g OPTION// gotcha
On old tmux, `set` for a window option (or `setw` for a session option) errored; modern tmux (3.x) accepts either since the tables were unified, so `setw` now signals intent rather than being required. Without `-g`, `setw` sets the option for the current window only, not future ones.