it's a terminal multiplexer that allows access to multiple terminal sessions in a single window. so, you can split terminals into panes. you can move, resize, and switch between them.
it's also useful for detaching processes from the controlling terminal. so, a SSH session can remain active without actually being visible. i recommend using tmux if you're doing remote work via ssh.
install tmux with sudo apt install tmux.
shortcuts:
tmux -V # show version
tmux # launch tmux
tmux new -s mysessionname # start new session with a name
tmux a -t mysessionname # attach to a named session
tmux ls # show list of tmux sessions
tmux a # attach
tmux attach -t 0 # reattach to a running tmux session
tmux kill-session -t 0 # end/kill session
CTRL+B, z # toggle current pane full screen
CTRL+B, c # add a new window
CTRL+B, n # move to next window
CTRL+B, p # move to previous window
CTRL+B, , # rename current window
CTRL+B, q # show pane numbers
CTRL+B, w # list windows and their numbers
CTRL+B, <window number> # move to window number
CTRL+B, % # horizontal split
CTRL+B, " # vertical split
CTRL+B, d # detach from and end session
CTRL+B, x # kill the current pane
CTRL+B, o # next pane
CTRL+B, { # move pane left
CTRL+B, } # move pane right
CTRL+B, ; # previous pane
CTRL+B, <UP ARROW> # switch between panes
CTRL+B, <DOWN ARROW> # switch between panes
CTRL+B, <LEFT ARROW> # switch between panes
CTRL+B, <RIGHT ARROW> # switch between panes
1. CTRL+B
2. [
3. Arrow keys or Shift + Page up/down
4. Control+C when donw with scrollback
don't like CTRL+B binding? you can rebind/remap it. Add set -g prefix C-a to your config.
~/.tmux.conf
tmux source-file ~/.tmux.conf