No point in making a file and then reading from it when hooks are sourced.
# first trigger graphics and tty subsystem
udevadm trigger --subsystem-match=graphics --subsystem-match=tty >/dev/null 2>&1
# add nomatch for full trigger
-echo " --subsystem-nomatch=graphics --subsystem-nomatch=tty " >> /tmp/udevtriggeropts
+udevtriggeropts="$udevtriggeropts --subsystem-nomatch=graphics --subsystem-nomatch=tty"
udevadm settle --timeout=30 >/dev/null 2>&1
[ -c /dev/null ] || mknod /dev/null c 1 3
source_all pre-trigger
# then the rest
-[ -f /tmp/udevtriggeropts ] && udevtriggeropts=$(while read line; do echo $line;done < /tmp/udevtriggeropts)
udevadm trigger $udevtriggeropts >/dev/null 2>&1
udevadm settle --timeout=30 >/dev/null 2>&1