systemd-stable/extras/volume_id

udev_volume_id - partition, filesystem, disklabel reader

This program is normally called from a udev rule, to provide udev with the
name, uuid or the filesystem type of a partition to name a device node.
udev_volume_id opens the blockdevice node specified at the commandline.
The following commandline switches are supported to specify what udev_volume_id
should print to stdout:

       no option prints all values
  -h   prints help text
  -l   prints the label of the partition
  -u   prints the uuid of the partition

udev_volume_id will only return successful if the string asked for, is not
empty. All trailing whitespace will be removed, spaces replaced by underscore
and slashes ignored.

The following rule will create a symlink named with the label string:
  KERNEL="[hs]d*", PROGRAM="/sbin/udev_volume_id -l %N", SYMLINK="%c"

If no label is found udev_volume_id exits with nonzero and the rule will be
ignored.

To give it a try, you may call it on the commandline:

  [root@pim udev.kay]# extras/volume_id/udev_volume_id /dev/hda3
  T:ext3
  L:Music Store
  N:Music_Store
  U:d2da42b5-bbd9-44eb-a72c-cc4542fcb71e

  [root@pim udev.kay]# extras/volume_id/udev_volume_id -l /dev/hda3
  Music_Store

  [root@pim udev.kay]# extras/volume_id/udev_volume_id -t /dev/hda3
  swap


Please send any comment/questions/concerns to me or:
	linux-hotplug-devel@lists.sourceforge.net

Kay Sievers <kay.sievers@vrfy.org>