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blkid -L label | -U uuid
blkid [-ghlv] [-c file] [-w file] [-o format]
[-s tag] [-t NAME=value] device [device ...]
blkid -p [-O offset] [-S size] [-o format] [-s tag]
[-u list] device [device ...]
blkid -i [-o format] [-s tag] device [device ...]
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
Note that blkid reads information directly from devices and for non-
root users it returns cached unverified information. It is better to
use lsblk --fs to get a user-friendly overview of filesystems and
devices. lsblk(8) is also easy to use in scripts. blkid is mostly
designed for system services and to test libblkid functionality.
blkid does not read information about removable devices by default.
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.
Read from cachefile instead of reading from the default cache
file /etc/blkid/blkid.tab. If you want to start with a clean
cache (i.e. don't report devices previously scanned but not nec-
essarily 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.
-i Display I/O Limits (aka I/O topology) information. The 'export'
output format is automatically enabled. This option could be
used together with -p option.
-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
ity use "-l -o device -t LABEL=<label>" and "-o list" in your
scripts rather than -L option.
Restrict probing functions to defined (comma separated) list of
"usage" types. Supported usage types are: filesystem, raid,
crypto and other. The list can be prefixed with "no" to specify
the usage types which should be ignored. For example:
blkid -p -u filesystem,other /dev/sda1
probes for all filesystems and others (e.g. swap) formats, and
blkid -p -u noraid /dev/sda1
probes for all supported formats exclude RAIDs. This option is
useful with -p only.
Look up one device that uses the uuid. For more details see the
Display blkid's output using the specified format. The format
parameter may be:
full print all tags (the default)
value print the value of the tags
list print the devices in a user-friendly format, this output
format is unsupported for low-level probing (-p or -i)
device print the device name only, this output format is always
enabled for -L and -U options
udev print key="value" pairs for easy import into the udev
export print key=value pairs for easy import into the environ-
ment. This output format is automatically enabled when
I/O Limits (-i option) are requested.
Probe at the given offset (only useful with -p). This option
could be used together with -i option.
-p Switch to low-level superblock probing mode (bypass cache).
-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)
Write the device cache to writecachefile instead of writing it
to the default cache file.
This functionality has never been implemented and the option is
no more supported on the recent blkid versions (>= v2.21).
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.
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.
blkid was written by Andreas Dilger for libblkid and improved by
Theodore Ts'o and Karel Zak.
The blkid command is part of the util-linux-ng package and is available
libblkid(3) findfs(8) wipefs(8)
Linux February 2009 BLKID(8)