In Ubuntu, UDev rules are stored in /etc/udev/rules.d/
UDev rules work by matching attributes of a device (such as SUBSYSTEM=="usb" - note the ==) and then firing off a command when all the rules match (such as RUN+="/my/script.sh")
To see what attributes a USB device located at /dev/sdc1 has
udevadm info -a -n /dev/sdc1
My device had a serial number programed into it
ATTRS{serial}=="C52404CA"
This was sufficient to uniquely identify my USB device, but you could also use other attributes such as the vendor name if necessary. I created a test rule to make sure things would work the way I wanted them to by making shell script to run when the rule was triggered.
Make a file at /home/dan/test.sh with the following content
#!/bin/bash
echo "hello!" > /home/dan/test.log
Change the permissions on the file to be executable
$ chmod 755 /home/dan/test.sh
Edit /etc/udev/rules.d/01-myrules.rules
ATTRS{SERIAL}=="C52404CA, RUN="/home/dan/test.sh"
And finally refreshing the udev rule.
$ sudo udevadm control --reload-rules
plugging in the device caused the rule to fire, but so did unplugging it.
This was solved by adding the ACTION=="add" option to the rule.
At this point, my rule looked like the following
ATTRS{serial}=="C52404CA", ACTION=="add", RUN+="/bin/mount /dev/%k /storage"
Edit: I later realized that this mounted the device for user root, so that was not very useful. See mounting permissions for how to fix this.
At this point, add that rule to the rules file, reload the udev rules, and you’re done!
Bonus Tip: To disable automatic device mounting in Gnome
install dconf-editor
sudo apt-get install dconf-tools
dconf-editor
Note that I did not run the command as root (you need to do it as the current user). Go to org.gnome.desktop.media-handling
and unchceck automount and automount-open
If you use cinnamon you have to go to org.cinnamon.desktop.media-handling.