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命令用途

blkid 命令用于定位和打印块设备的属性，主要用于识别存储设备（如磁盘、分区等）的类型、标签、UUID（通用唯一标识符）等信息。通过 blkid，用户可以迅速查找设备的相关信息，尤其是在进行文件系统管理时非常有用。

常用用法示例

  1. 查看所有块设备的信息

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    blkid

    列出所有块设备及其属性（如UUID、标签、文件系统类型等）。

  2. 查看某个设备的UUID

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    blkid /dev/sda1
    /dev/sda1: UUID="e9a2c3f9-0e7d-4db8-b5a6-fb83616e5f6b" TYPE="ext4"

    显示 /dev/sda1 的UUID。

  3. 使用标签查找设备

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    blkid -L "mylabel"
    /dev/sdb1: UUID="e9a2c3f9-0e7d-4db8-b5a6-fb83616e5f6b" TYPE="ext4"

    找到与标签 mylabel 匹配的设备。

  4. 列出所有支持的文件系统

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    blkid -k

    列出所有已知的文件系统类型和RAID类型。

  5. 查看块设备的文件系统类型

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    blkid -o value -s TYPE /dev/sda1
    ext4

    返回 /dev/sda1 的文件系统类型.

  6. 低级探测块设备

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    blkid -p /dev/sda1

    显示包括分区信息在内的详细设备信息。

  7. 查询设备的UUID

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    blkid -U e9a2c3f9-0e7d-4db8-b5a6-fb83616e5f6b

    返回具有指定UUID的设备路径。

  8. 按设备标签查找设备

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    blkid --match-token LABEL=mylabel

    显示符合指定标签的设备信息。

常用参数选项

  • -c, –cache-file cachefile
    使用指定的缓存文件，而不是默认的缓存文件。用于提升查询效率，尤其在缓存信息量大的情况下。

  • -d, –no-encoding
    不对非打印字符进行编码。默认情况下，非打印字符会用 ^ 或 M- 进行表示。

  • -g, –garbage-collect
    对 blkid 缓存进行垃圾回收，移除不再存在的设备。

  • -L, –label label
    查找使用指定标签的设备。例如，查找所有标签为 mylabel 的设备。

  • -n, –match-types list
    限制探测功能，仅对指定的超级块类型进行探测。支持 no 前缀来忽略特定类型。

  • -o, –output format
    指定输出格式。常见格式有 full、value、list、device 等，分别显示详细信息、仅显示值、简洁格式或设备名。

  • -p, –probe
    切换到低级别探测模式，绕过缓存，提供更详细的设备信息。

  • -U, –uuid uuid
    根据指定的UUID查找设备。这是通过UUID快速识别设备的一种方式。

原厂文档

NAME 

   blkid - locate/print block device attributes

SYNOPSIS 

   blkid --label label | --uuid uuid

   blkid [--no-encoding --garbage-collect --list-one --cache-file
   file] [--output format] [--match-tag tag] [--match-token
   NAME=value] [device...]

   blkid --probe [--offset offset] [--output format] [--size size]
   [--match-tag tag] [--match-types list] [--usages list]
   [--no-part-details] device...

   blkid --info [--output format] [--match-tag tag] device...

DESCRIPTION 

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

   It is recommended to use lsblk(8) command to get information about
   block devices, or lsblk --fs to get an overview of filesystems, or
   findmnt(8) to search in already mounted filesystems.

      lsblk(8) provides more information, better control on
      output formatting, easy to use in scripts and it does not
      require root permissions to get actual information. blkid
      reads information directly from devices and for non-root
      users it returns cached unverified information. blkid is
      mostly designed for system services and to test
      libblkid(3) functionality.

   When device is specified, tokens from only this device are
   displayed. It is possible to specify multiple device arguments on
   the command line. If none is given, all partitions or
   unpartitioned devices which appear in /proc/partitions are shown,
   if they are recognized.

   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 specified devices.

   For security reasons blkid silently ignores all devices where the
   probing result is ambivalent (multiple colliding filesystems are
   detected). The low-level probing mode (-p) provides more
   information and extra exit status in this case. It’s recommended
   to use wipefs(8) to get a detailed overview and to erase obsolete
   stuff (magic strings) from the device.

OPTIONS 

   The size and offset arguments may be followed by the
   multiplicative suffixes like KiB (=1024), MiB (=1024*1024), and so
   on for GiB, TiB, PiB, EiB, ZiB and YiB (the "iB" is optional,
   e.g., "K" has the same meaning as "KiB"), or the suffixes KB
   (=1000), MB (=1000*1000), and so on for GB, TB, PB, EB, ZB and YB.

   -c, --cache-file cachefile
       Read from cachefile instead of reading from the default cache
       file (see the CONFIGURATION FILE section for more details). If
       you want to start with a clean cache (i.e., don’t report
       devices previously scanned but not necessarily available at
       this time), specify /dev/null.

   -d, --no-encoding
       Don’t encode non-printing characters. The non-printing
       characters are encoded by ^ and M- notation by default. Note
       that the --output udev output format uses a different encoding
       which cannot be disabled.

   -D, --no-part-details
       Don’t print information (PART_ENTRY_* tags) from partition
       table in low-level probing mode.

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

   -H, --hint setting
       Set probing hint. The hints are an optional way to force
       probing functions to check, for example, another location. The
       currently supported is "session_offset=number" to set session
       offset on multi-session UDF.

   -i, --info
       Display information about I/O Limits (aka I/O topology). The
       'export' output format is automatically enabled. This option
       can be used together with the --probe option.

   -k, --list-filesystems
       List all known filesystems and RAIDs and exit.

   -l, --list-one
       Look up only one device that matches the search parameter
       specified with the --match-token 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 (but see below note about
       udev). 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.

       This option forces blkid to use udev when used for LABEL or
       UUID tokens in --match-token. The goal is to provide output
       consistent with other utils (like mount(8), etc.) on systems
       where the same tag is used for multiple devices.

   -L, --label label
       Look up the device that uses this filesystem label; this is
       equal to --list-one --output device --match-token LABEL=label.
       This lookup method is able to reliably use /dev/disk/by-label
       udev symlinks (dependent on a setting in /etc/blkid.conf).
       Avoid using the symlinks directly; it is not reliable to use
       the symlinks without verification. The --label option works on
       systems with and without udev.

       Unfortunately, the original blkid(8) from e2fsprogs uses the
       -L option as a synonym for -o list. For better portability,
       use -l -o device -t LABEL=label and -o list in your scripts
       rather than the -L option.

   -n, --match-types list
       Restrict the probing functions to the specified
       (comma-separated) list of superblock types (names). The list
       items may be prefixed with "no" to specify the types which
       should be ignored. For example:

       blkid --probe --match-types vfat,ext3,ext4 /dev/sda1

       probes for vfat, ext3 and ext4 filesystems, and

       blkid --probe --match-types nominix /dev/sda1

       probes for all supported formats except minix filesystems.
       This option is only useful together with --probe.

   -o, --output format
       Use the specified output format. Note that the order of
       variables and devices is not fixed. See also option -s. 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 (--probe or
           --info).

           This output format is DEPRECATED in favour of the lsblk(8)
           command.

       device
           print the device name only; this output format is always
           enabled for the --label and --uuid options

       udev
           print key="value" pairs for easy import into the udev
           environment; the keys are prefixed by ID_FS_ or ID_PART_
           prefixes. The value may be modified to be safe for udev
           environment; allowed is plain ASCII, hex-escaping and
           valid UTF-8, everything else (including whitespaces) is
           replaced with '_'. The keys with _ENC postfix use
           hex-escaping for unsafe chars.

           The udev output returns the ID_FS_AMBIVALENT tag if more
           superblocks are detected, and ID_PART_ENTRY_* tags are
           always returned for all partitions including empty
           partitions.

           This output format is DEPRECATED.

       export
           print key=value pairs for easy import into the
           environment; this output format is automatically enabled
           when I/O Limits (--info option) are requested.

           The non-printing characters are encoded by ^ and M-
           notation and all potentially unsafe characters are
           escaped.

       json
           Print the tags entries in JSON objects.

   -O, --offset offset
       Probe at the given offset (only useful with --probe). This
       option can be used together with the --info option.

   -p, --probe
       Switch to low-level superblock probing mode (bypassing the
       cache).

       Note that low-level probing also returns information about
       partition table type (PTTYPE tag) and partitions (PART_ENTRY_*
       tags). The tag names produced by low-level probing are based
       on names used internally by libblkid and it may be different
       than when executed without --probe (for example
       PART_ENTRY_UUID= vs PARTUUID=). See also --no-part-details.

   -s, --match-tag tag
       For each (specified) device, show only the tags that match
       tag. It is possible to specify multiple --match-tag 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 --match-tag none with no other
       options.

   -S, --size size
       Override the size of device/file (only useful with --probe).

   -t, --match-token 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.

   -u, --usages list
       Restrict the probing functions to the specified
       (comma-separated) list of "usage" types. Supported usage types
       are: filesystem, raid, crypto and other. The list items may be
       prefixed with "no" to specify the usage types which should be
       ignored. For example:

       blkid --probe --usages filesystem,other /dev/sda1

       probes for all filesystem and other (e.g., swap) formats, and

       blkid --probe --usages noraid /dev/sda1

       probes for all supported formats except RAIDs. This option is
       only useful together with --probe.

   -U, --uuid uuid
       Look up the device that uses this filesystem uuid. For more
       details see the --label option.

   -h, --help
       Display help text and exit.

   -V, --version
       Print version and exit.

EXIT STATUS 

   If the specified device or device addressed by specified token
   (option --match-token) was found and it’s possible to gather any
   information about the device, an exit status 0 is returned. Note
   the option --match-tag filters output tags, but it does not affect
   exit status.

   If the specified token was not found, or no (specified) devices
   could be identified, or it is impossible to gather any information
   about the device identifiers or device content an exit status of 2
   is returned.

   For usage or other errors, an exit status of 4 is returned.

   If an ambivalent probing result was detected by low-level probing
   mode (-p), an exit status of 8 is returned.

CONFIGURATION FILE 

   The standard location of the /etc/blkid.conf config file can be
   overridden by the environment variable BLKID_CONF. The following
   options control the libblkid library:

   SEND_UEVENT=<yes|not>
       Sends uevent when
       /dev/disk/by-{label,uuid,partuuid,partlabel}/ symlink does not
       match with LABEL, UUID, PARTUUID or PARTLABEL on the device.
       Default is "yes".

   CACHE_FILE=<path>
       Overrides the standard location of the cache file. This
       setting can be overridden by the environment variable
       BLKID_FILE. Default is /run/blkid/blkid.tab, or /etc/blkid.tab
       on systems without a /run directory.

   EVALUATE=<methods>
       Defines LABEL and UUID evaluation method(s). Currently, the
       libblkid library supports the "udev" and "scan" methods. More
       than one method may be specified in a comma-separated list.
       Default is "udev,scan". The "udev" method uses udev
       /dev/disk/by-* symlinks and the "scan" method scans all block
       devices from the /proc/partitions file.

ENVIRONMENT 

   Setting LIBBLKID_DEBUG=all enables debug output.

AUTHORS 

   blkid was written by Andreas Dilger for libblkid and improved by
   Theodore Ts’o and Karel Zak.

SEE ALSO 

   libblkid(3), findfs(8), lsblk(8), wipefs(8)

REPORTING BUGS 

   For bug reports, use the issue tracker
   <https://github.com/util-linux/util-linux/issues>.

AVAILABILITY 

   The blkid command is part of the util-linux package which can be
   downloaded from Linux Kernel Archive
   <https://www.kernel.org/pub/linux/utils/util-linux/>. This page is
   part of the util-linux (a random collection of Linux utilities)
   project. Information about the project can be found at 
   ⟨https://www.kernel.org/pub/linux/utils/util-linux/⟩. If you have a
   bug report for this manual page, send it to
   util-linux@vger.kernel.org. This page was obtained from the
   project's upstream Git repository
   ⟨git://git.kernel.org/pub/scm/utils/util-linux/util-linux.git⟩ on
   2024-02-02. (At that time, the date of the most recent commit that
   was found in the repository was 2024-01-30.) If you discover any
   rendering problems in this HTML version of the page, or you
   believe there is a better or more up-to-date source for the page,
   or you have corrections or improvements to the information in this
   COLOPHON (which is not part of the original manual page), send a
   mail to man-pages@man7.org