SYNOPSIS

       blkid  [ -ghlv ] [ [ -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     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.

       -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 blkid's 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.

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 1.40.3         December 2007                        BLKID(8)