The command you can use to edit the config file would be
sudo nano /opt/retropie/configs/zxspectrum/.zesaruxrc
Place your roms in /home/pi/RetroPie/roms/zxspectrum folder. ZEsarUX supports .P, .81 and .Z81 formats for the ZX81.
Once you’ve installed ZEsarUX, there will be a +Start ZEsarUX script. You can use this to launch the emulator and have a play with a ZX81 computer. You can also load tapes using Smart load option from the menu (F5).
Roms should automatically appear in ES. If they do not, then it’s because the format isn’t included in es_systems.cfg and you will need to edit the file. Let me know if you’re not sure how to do this.
I managed to install ZEsarUX at lunchtime. I noticed that it seems to have changed the default Spectrum emu to itself. Not a problem, I know you can select individual emus for different roms.
I still need to stick the roms in the spectrum folder, and edit the config file. I have been using WinSCP to transfer roms quite successfully. I also use this at work to move files around, and can edit text files using it. I dont know why I thought this would be any different. Sometimes you can over think things!
Seeing as though ZEsarUX emulates both ZX81 and Spectrum, and that I need to drop the ZX81 roms in the Spectrum folder, does this mean that the best I can hope for is to run ’81 games from the Spectrum section in Emulation Station? Would it be possible to configure so that there is a ZX81 option along with all the other systems? Or am I trying to run before I can walk?