Tmux is terminal multiplexer. Kinda like old screen, but with much more functionality.
When I work on my servers, it's pretty common that I have to do the same things to multiple servers. To make my life easier I start tmux, and in there start many “windows", each related to work on single server.
I name the windows in a way that let's me quickly find them, without false positives.
For example, if I'd have to upgrade servers db1..db5 then I'd create windows “up-db1" .. “up-db5", and each window would work on single server.
This is already scriptable – let's assume I'd want to show uptime in all of the windows, I can:
tmux lsw -F '#W' | grep -E '^up-db[0-9]+$' | xargs -r -d$'\n' -I% tmux send-keys -t % uptime Enter
But this gets tedious fast.