tmux / byobu

How to stay connected.

Why we use tmux (or byobu)

Even though we are using SSH Access to start and stop our POCS software, we want the software to continue running after we have disconnected and so we can't just run things directly in the terminal.

Instead, we need to run them in a sort-of background terminal (technically it's called a terminal multiplexer).

Both byobu and tmux do exactly that. So the idea is that you ssh into your remote computer, then you start byobu (or tmux) if it's your first connection, otherwise you can "attach" to the existing session by typing byobu a (or tmux a).

As a bonus, we can also split our screen into multiple "windows" and "panes" and have a different shell in each of these. For example, you can keep the log files open in a lower pane and run the commands in an upper pane. See the images below for examples.

What's the difference?

byobu is actually just a wrapper around tmux, which gives some better defaults and a nice-looking status prompt. byobu is available by default on ubuntu and many ubuntu tutorials refer to it.

tmux is basically the same thing but a little more "raw". On the other hand, tmux tends to be more widely available on non-ubuntu systems.

The big difference comes down to the "command key", with byobu using Ctrl-a and tmux using Ctrl-b. 🀷

Attach to byobu session

When observing, you can use byobu ( to split your terminal into multiple smaller panels with different processes running in each. That way, you can view the running POCS and log files all at once, which is especially convenient when logging in remotely. It also allows other people on your team to join the same byobu session and see how the unit is doing.

By default, byobu should already be installed on Ubuntu. To attach, enter byobu in a new terminal window on the NUC. Then, you can jump between panels by pressing CTRL-a, letting go, then pressing an arrow key ↑ ↓ β†’ ← in the direction you want to move. More commands (ie. splitting screens, resizing screens, creating windows etc) are listed below.

Byobu cheat sheet

The commands are the same for tmux but instead of Ctrl-a it's Ctrl-b.

CTRL-a then ? - help

CTRL-a then \ - kill byobu (& all running processes)

CTRL-a then CTRL-d - detach without kill (or just close the terminal window)

Windows management

CTRL-a then c - create new window

CTRL-a then k - kill current window

CTRL-a then p - goto previous window

CTRL-a then n - goto next window

CTRL-a then [window number] - goto to a specific window (see bottom bar of terminal for all window numbers)

Panels management

CTRL-a then % - split current panel vertically

CTRL-a then | - split current panel horizontally

CTRL-a then TAB - next panel

CTRL-a then ↑, - switch panels (with arrow keys)

CTRL-a then ↓,

CTRL-a then β†’,

CTRL-a then ←

Hold CTRL-a and press ↑, - resize panels vertically

Hold CTRL-a and press ↓

Hold CTRL-a and press ←, - resize panels horizontally

Hold CTRL-a and press β†’

Scroll up page buffer

CTRL-athen [ - scroll with ↑ ↓ arrows, then press Enter to exit

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2023 Project PANOPTES