How to send message to every tmux session

Send message to every tmux session.

At first, ensure that message display time is increased to at least a couple of seconds.

set-option -g display-time 5000

Send a message to every tmux session.

$ tmux list-clients -F "#{client_name}" | xargs -I{} tmux display-message -c {} "Build finished\!"

Display previous messages.

$ tmux show-messages

Mon Jul 18 14:03:22 2021 Ansible lab.playbook successfully executed
Mon Jul 18 14:21:10 2021 Ansible home.playbook successfully executed
Mon Jul 18 20:12:41 2021 System upgraded
Mon Jul 19 00:13:46 2021 Build finished!