[Solved]Automating a script for a usb device on systemd?

Question

Solution:See 3rd post by 65kid.
   Ok I'm trying to learn how to automate the execution of a script I wrote to run whenever a specific usb device is plugged in. In this case a usb flash drive with a specific partition identified though UUID following the path /dev/disk/by-uuid/specified-partion's-uuid.
   Basically the script uses rsync to update a snapshot of my system which I made bootable on this device. following the guide given in the wiki on full system backup using rsync I edited the --exclude options to ignore the contents of my /boot/ /etc/fstab and /etc/mkinitcpio.conf since the fstab entries, hooks array and initramfs and kernel images generated with them needed to be changed so as to make this snapshot bootable and adapted for use on the usb stick.
the ultimate goal is to have a bootable snapshot the can be updated with whatever changes have been made with my system(i.e. pacman -Syu updates,config changes etc...) while leaving out the important things needed to have the usb still bootable afterwards. I've already succeeded at getting the script to work but I have to mount it manually then execute the script myself and I know that it works afterwards as I can still boot from the stick afterwards.
   This is not a question about rsync (which is why the script isn't posted here), to repeat myself, It's about how to execute ANY custom script whenever a specific device is plugged in. More specifically when a storage device with a certain uuid is detected after the device has been plugged in. I believe it may be different for running pure systemd and so that was the reasoning for having it mentioned in the subjects title(if I'm wrong then correct my understanding). If anything a few pointers on where to look would be appreciated. I've been googling and reading the wiki a bit with nothing specific on how to approach this. If an example of the script is requested I'll post it but it's not relevent to my question.
   For a general veiw of my setup regarding external storage volumes I do not automount anything as I do not use all the things I plug in in the same manner. Some of the stuff I do requires them to be unmounted or  mounted to different mount points(specified by me). The script handles the mounting part by itself just fine. The idea I have is to run it automatically when the flash drive is present. Any suggestions?
Last edited by Thme (2012-12-29 00:06:56)

Answer 1

Awebb wrote:You "seem to remember" has FUD potential, could you care to find the post again?
he is probably referring to this: https://bbs.archlinux.org/viewtopic.php … 2#p1113682
imho this is way different, the SYSTEMD_WANTS tag is completely ok to use. yes, he may be mounting the drive from the script, but imho he is not "exploiting" anything here. I personally don't see a much more elegant way to do this.
these automount udev rules were however crappy and hackish. They were created by people who are like "but udisks is bloat!!1!" and whoever wrote them didn't really seem to know what he was doing because, for example, unmounting a device after it was unplugged from the system is completely non-sense.