How to run a tmux command from inside a session?
Short answer
Press prefix :, then type a tmux command without the leading tmux word:
split-window -h
resize-pane -D 10
source-file ~/.tmux.confThe command runs against the server you are attached to, right now.
Details
prefix : opens the command prompt (command-prompt), a one-line input at the bottom of the
screen. It is the interactive twin of the shell CLI: the same commands, the same flags, minus the
tmux word in front. Anything you would run as tmux split-window -h becomes split-window -h
here.
Two moments where it earns its place. First, trying something once before you commit to it: run
resize-pane -D 10 or a new set from the prompt, see the effect, then decide whether it belongs
in ~/.tmux.conf. Second, reaching a command that has no default key binding, without dropping to
a shell.
A template can prompt for input before it runs. command-prompt -p "new name:" "rename-window '%%'" shows the prompt new name:, then substitutes whatever you type for %%. With several
-p prompts, use %1, %2 and so on to place each answer. That is how the built-in bindings for
renaming and finding are wired, and how you can build your own.
Verified on tmux 3.2a.