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BLKID(8)		    System Manager's Manual		      BLKID(8)

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

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

DESCRIPTION
       The blkid program is the	command-line interface to  working  with  lib-
       blkid(3)	 library.  It can determine the	type of	content	(e.g. filesys-
       tem,  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 cachefile
	      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. don't report devices previously scanned but	not  necessar-
	      ily available at this time), specify /dev/null.

       -g     Perform  a  garbage collection pass on the blkid cache to	remove
	      devices which no longer exist.

       -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  De-
	      vice  Mapper,  EVMS, LVM,	MD, and	finally	regular	block devices.
	      If this option is	not specified, blkid will print	all of the de-
	      vices that match the search parameter.

       -o format
	      Display  blkid's	output using the specified format.  The	format
	      parameter	may be full (the default), value (only print the value
	      of  the  tags),  list (print the devices in a user-friendly for-
	      mat), or device (only print the device name).

       -L     Print the	devices	in a user-friendly list	format.	 This  is  the
	      equivalent of using the option -o	list.

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

       -t NAME=value
	      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 the specified devices are searched.

       -v     Display version number and exit.

       -w writecachefile
	      Write  the  device cache to writecachefile instead of writing it
	      to the default cache file	/etc/blkid.tab.	 If you	don't 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  op-
	      tion.

       device Display  tokens  from only the specified device.	It is possible
	      to give multiple device 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 re-
       turned.	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 1.43.4	 January 2017			      BLKID(8)

NAME | SYNOPSIS | DESCRIPTION | OPTIONS | RETURN CODE | AUTHOR | AVAILABILITY | SEE ALSO

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