assess your baseline.

There are a variety of technologies at play and each one needs to work end-to-end. The core of the debugging is an awk script found at termstandard/colors which emits a color test (see example output below).

script.

'BEGIN {
    s="/\\/\\/\\/\\/\\"; s=s s s s s s s s;
    for (colnum = 0; colnum<77; colnum++) {
        r = 255-(colnum*255/76);
        g = (colnum*510/76);
        b = (colnum*255/76);
        if (g>255) g = 510-g;
        printf "\033[48;2;%d;%d;%dm", r,g,b;
        printf "\033[38;2;%d;%d;%dm", 255-r,255-g,255-b;
        printf "%s\033[0m", substr(s,colnum+1,1);
    }
printf "\n";
}'

example outputs.

correct output.

incorrect output.

Assert truecolor is working, using the above script, in the order listed below:

1. The local shell, under the terminal emulator of choice.
2. (If needed) The local shell, inside of tmux
3. The remote shell, over SSH
4. The remote shell, over mosh
5. The remote shell, over mosh, inside of a tmux session

If you encounter an incorrect output at any one of these steps, a search and application of a fix gives you a sane foundation to apply another layer (and potential round of debugging) to continue onwards.

final setup.

software.

• Kitty v0.28.1
• mosh v1.4
  • For Ubuntu 22.04, mosh will need to be build from source. Download the .tar.gz and follow the instructions under Latest release.
• tmux v3.2a

configurations.

Few changes were required for my setup which are listed below.

.tmux.conf

The only change required for tmux.

set-option -ga terminal-overrides ",xterm-256color:Tc"

.bashrc

More of an "unconfiguration," do not set $TERM in your bash shell.