loadkeys
loadkeys is used to remap keys in linux console.
How I remapped caps to control:
# confirm the existince of this file
ls /usr/share/kbd/keymaps/i386/qwerty/defkeymap.map.gz
cp /usr/share/kbd/keymaps/i386/qwerty/defkeymap.map.gz ./
gunzip defkeymap.map.gz
nvim defkeymap.map
# Set keycode 58 to Control in defkeymap.map
# keycode 58 = Control
# Finally in console I did:
sudo loadkeys defkeymap.map