A typical situation may be:
$ tmux
[0] $ ssh example.com
$ tmux attach
[0] $
I open a tmux session, then ssh in to a server and attach to an existing tmux session. At this point I have one tmux session inside another. How do I send commands to the inner tmux session?
Note: Both tmux sessions have the same key bindings.
Best Answer
The
send-prefix
command can be used to send your prefix keystroke to (the process running in) the active pane. By default, the prefix is C-b and C-b is bound tosend-prefix
(so that hitting it twice sends a single C-b to the active pane). This is just what we need to access the bindings of the inner tmux instance.The first C-b is captured by the “outer” tmux instance as its prefix key. The second one is captured by the “outer” tmux instance and triggers its C-b binding (
send-prefix
). This sends a C-b to the outer instance’s active pane. The process running in this pane is (ultimately, through an ssh instance) the “inner” tmux instance. It captures the C-b as its prefix key. Now your next keystroke will be passed through the outer tmux instance and captured by the inner one to trigger a binding.To trigger the c binding (
new-window
) in a second-level instance of tmux, you would type C-b C-b c. For a third-level instance of tmux you would type C-b C-b C-b C-b c.This doubling for each level can be annoying if you are commonly dealing with multiple layers of tmux. If you can spare some other key, you could make a non-prefixed binding to make things (possibly) easier to type:
Create new window in second-level tmux: C-\ c
Create new window in third-level tmux: C-^ c (or C-\ C-\ c)
If you have a limited number of tmux commands that you want to (easily) send to the lower-level tmux instances, you might instead use
send-keys
to create some specific bindings (possibly just in your top-level tmux instance):Create new window in second-level tmux: C-b C-c
Create new window in third-level tmux: C-b C