HOWTO: Set font size in virtual consoles

In Debian you can have virtual terminal consoles, which are different from a terminal emulator window. Before Buster came along, a lot of commands could be run in a terminal emulator, but these days, more often than not, commands have to be run in a virtual console instead. The difference is that a virtual console is fullscreen, not a window, and doesn’t run under the GUI, which goes into the background at that point.
You can have six separate consoles that you switch between by pressing Ctrl-Alt-Fx where x is 1 to 6, i.e. the F1 to F6 keys. To switch back to the GUI you press Ctrl-Alt-F7.
The next issue is the font size which I tend to find rather too small. Fortunately this is easy to fix. Use nano to edit /etc/default/console-setup and change the following lines to read as follows:
This gives us quite a large easy to read font. 
Run the command setupcon to apply it immediately, it should become the permanent setting.

The fonts are all stored in /usr/share/consolefonts directory so you can look up what is available if you want something different. What I haven’t done yet is work out if I can change the colour from white.