marlin/buildroot/bin/backup_ramps

#!/usr/bin/env bash

PINS="Marlin/src/pins"
RAMPS="$PINS/ramps/pins_RAMPS.h"
BKUP="$PINS/ramps/pins_RAMPS.backup.h"

[[ -f $RAMPS ]] && cp "$RAMPS" "$BKUP"