I'm setting up a new installation of Debian Stretch. Because it's on custom NAS box, there's one small gripe I have - original software was booted from a USB memory module molded on to the motherboard. I'm booting Debian from something else, but it automatically recognizes and mounts all partitions from that USB memory. So I was thinking I will cook myself a small script to unmount those partitions and run it from rc.local, except now I found that rc.local is in fact a deprecated backwards compatibility feature for a backwards compatibility feature and should be avoided as such.
So how do I run this small script:
umount /dev/sdd1 /dev/sdd2 /dev/sdd3 /dev/sdd4 /dev/sdd5
At boot time? It's not a daemon so I think it makes no sense to dwell into systemd as suggested for daemon processes in that other question&discussion I found here.
Or maybe there's a way I can prevent Debian from mounting that usb memory to begin with?