BLKID(8)							      BLKID(8)



NAME
       blkid - command-line utility to locate/print block device attributes

SYNOPSIS
       blkid  [  -hlv ] [ [ -c cachefile ] -w writecachefile ] [ -o format ] [
       -s tag ] [ -t NAME=value ] [ device ...	]

DESCRIPTION
       The blkid program is the command-line interface to working  with  libu
       uid(3) library.	It can determine the type of content (e.g. filesystem,
       swap) a block device holds, and	also  attributes  (tokens,  NAME=value
       pairs) from the content metadata (e.g. LABEL or UUID fields).

       blkid  has  two	main forms of operation: either searching for a device
       with a specific NAME=value pair, or displaying NAME=value pairs for one
       or more devices.

OPTIONS
       -c     Read  from  cachefile  instead of reading from the default cache
	      file /etc/blkid.tab.  If you want to start with  a  clean  cache
	      (i.e.  dont report devices previously scanned but not necessar
	      ily available at this time), specify /dev/null.

       -h     Display a usage message and exit.

       -l     Look up one device that matches the search  parameter  specified
	      using  the  -t option.  If there are multiple devices that match
	      the specified search parameter, then the device with the highest
	      priority	is  returned, and/or the first device found at a given
	      priority.  Device types in  order  of  decreasing  priority  are
	      Device Mapper, EVMS, LVM, MD, and finally regular block devices.
	      If this option is not specified, blkid will  print  all  of  the
	      devices that match the search parameter.

       -o     Display  blkids  output using the specified format.  The format
	      parameter may be full, (the default),  value,  (only  print  the
	      value  of  any  tags printed by blkid) or device (only print the
	      device name).

       -s     Show only the tags for each (specified) device that  match  tag.
	      It  is  possible	to  specify multiple -s options.  If no tag is
	      specified,  then	all  tokens  are  shown  for  all  (specified)
	      devices.	In order to just refresh the cache without showing any
	      tokens use -s none with no other options.

       -t     Search for block devices with tokens named NAME  that  have  the
	      value  value,  and  display any devices which are found.	Common
	      values for NAME include TYPE, LABEL, and UUID.  If there are  no
	      devices specified on the command line, all block devices will be
	      searched; otherwise, only search the devices  specified  by  the
	      user.

       -v     Display version number and exit.

       -w     	 Write	the  device  cache  to	writecachefile
	      instead of writing it to the default cache file  /etc/blkid.tab.
	      If you dont want to save the cache to the default file, specify
	      /dev/null.  If not specified it will be the same	file  as  that
	      given by the -c option.

       
	      Display  tokens  from only the specified device.	It is possible
	      to give multiple  options on the command line.  If  none
	      is  given,  all  devices	which  appear  in /proc/partitions are
	      shown, if they are recognized.

RETURN CODE
       If the specified token was found, or if any tags were shown from (spec
       ified) devices 0 is returned.  If the specified token was not found, or
       no (specified) devices could be	identified,  an  exit  code  of  2  is
       returned.  For usage or other errors, an exit code of 4 is returned.

AUTHOR
       blkid was written by Andreas Dilger for libblkid.

AVAILABILITY
       blkid is part the e2fsprogs package since version 1.26 and is available
       from http://e2fsprogs.sourceforge.net.

SEE ALSO
       libblkid(3)



E2fsprogs version 1.40-WIP	 November 2006			      BLKID(8)