How can I make tmux monitor a window for inactivity? I've switched from GNU Screen to tmux. They're both similar, except that tmux is still maintained. GNU Screen has a `C-a _` ("silence") command. This command makes GNU Screen monitor the current window and alert me when there's been 30 seconds of inactivity. This is quite useful: for example, GNU Screen can watch a long `apt-get dist-upgrade` process and alert me when dpkg has a question for me. Does tmux have an equivalent command? I tried searching the Web but didn't find an answer.

The manpage reveals the answer. You will need tmux 1.4 (released Dec. 2010) or better.

Press `Ctrl`+`B` then enter the command:

`:setw monitor-silence 30`

To identify all quiet windows in the session, apply the setting to all windows:

`:setw -g monitor-silence 30`