Since no one's mentioned it in the comments, I occasionally use tmux's pane synchronization to run the same command across multiple panes: CTRL-B, then "set syn

Since no one's mentioned it in the comments, I occasionally use tmux's pane synchronization to run the same command across multiple panes: CTRL-B, then "set synchronize-panes". I've done this to do things like log into multiple different servers and startup some process all at the same time. 'set synchronize-panes' toggles this behavior, so when you're done, run the same command again to disable it.