Looking at correcting an issue in /etc/init.d/hostapd on Debian. However, I have no clue what this line of code does nor how it works
[ -n "$DAEMON_CONF" ] || exit 0
[ -n "not empty" ] || exit 0
If the expression in
 returns false, do the thing after the or
exit 0). Otherwise, it will short circuit and the next statement will be evaluated.