A while ago I reconfigured two of the buttons on a gaming mouse to give me Copy and Paste at the file and folder level in Thunar. I did that by getting button numbers from xev and reconfiguring their function with xbindkeys.

I'm trying to see if I can do something similar with two of the extra keys on an old eMachines keyboard. The keys are designated Copy and Paste and probably did exactly that back in the days of XP, but they do not record any signal when I test them on xev.

I installed and ran evtest, which gave me the scancodes for them, but hexadecimal event codes are not workable as xbindkeys configuration entries, the way button press numbers are for a mouse. Is there some intermediate translation from scancodes to X-readable entries, perhaps in systemd, or is it a matter of changing something at serious kernel level? If it does go that deep, I probably wouldn't do it – I'm thinking of it as just a tweak to get a fast way to copy and paste files from place to place.

Distro: Xubuntu Core 15.10 with limited software added, adding more all the time.

xmodmap may work for you.
Our friends over at Arch have good docs on it : https://wiki.archlinux.org/index.php/Xmodmap

I used to use it, but stopped cause I changed distros often.

Good luck !

Thanks for the reply, but xmodmap also uses only X-readable keycodes/keysyms, not the scancodes that are buried somewhat deeper in the system.