my question is simple. I have two windows in tmux session, 1 and 2. How can I merge these two windows into one window split horizontally/vertically? I couldn't find an answer in manpage, so I'm asking here.
I think you're looking for
join-pane [-bdhv] [-l size | -p percentage] [-s src-pane] [-t dst-pane] (alias: joinp) Like split-window, but instead of splitting dst-pane and creating a new pane, split it and move src-pane into the space. This can be used to reverse break-pane. The -b option causes src-pane to be joined to left of or above dst-pane.
You can use this with the command-line (