# Define a label for a specific device
LABEL="my_usb_device", ATTRS{idVendor}=="1234", ATTRS{idProduct}=="5678"

# Reference a label in a GOTO
SUBSYSTEM=="usb", GOTO="my_peripheral"

# Define environment variables
ENV{DEVTYPE}="usb_device"
ENV{USB_DRIVER}="usb-storage"

# Reference environment variables
ENV{DEVTYPE}=="usb_device", SYMLINK+="usb_storage_%k"

# Variable substitution
SYMLINK+="disk/by-label/$env{ID_FS_LABEL}"

# Label for a section of rules
LABEL="my_peripheral"
SUBSYSTEM=="usb", MODE="0666"

# End label
LABEL="end_my_rules"