Reply To: Serial console to my Pi gateway shows escape codes instead of colours and htop is a mess

It’s the Pi side, not the terminal program. Two things are missing on a serial login that SSH gives you for free.

The terminal type: SSH passes your TERM along (xterm-256color from PuTTY). The serial getty sets TERM to vt220, which has no colour, so programs that check TERM fall back or print raw codes. Check with echo $TERM.

The window size: there’s no way for the serial line to tell the Pi how big your window is, so it assumes 80×24 and never changes.

I put this in ~/.bashrc on every box I console into:

case "$(tty)" in
  /dev/ttyS0|/dev/ttyAMA0|/dev/serial0)
    export TERM=xterm-256color
    stty rows 50 cols 160      # match your PuTTY window
    ;;
esac

If you install the xterm package you can type resize instead of hardcoding the size, it asks the terminal and sets it.

Your script’s colours will then work, assuming the logging library checks TERM.