I needed this too, so I created this udev rules file to enable use of
particle flash --usb without
Credits to the creator of the Teensy board (Paul Stoffregen - [Name added by ScruffR]) for the basis of this udev file.
Here’s another good trick from the Teensy creator to prevent having the serial port change device each time you plug the device in:
If using USB Serial you get a new device each time (Ubuntu >9.10)
eg: /dev/ttyACM0, ttyACM1, ttyACM2, ttyACM3, ttyACM4, etc
apt-get remove --purge modemmanager (reboot may be necessary)