blob: 9c42686e95fb391d737e167355f92e16d0ae2b11 [file] [log] [blame]
lh9ed821d2023-04-07 01:36:19 -07001.\" Copyright 2000 Andreas Dilger (adilger@turbolinux.com)
2.\"
3.\" This man page was created for blkid from e2fsprogs-1.25.
4.\"
5.\" This file may be copied under the terms of the GNU Public License.
6.\"
7.\" Based on uuidgen, Mon Sep 17 10:42:12 2000, Andreas Dilger
8.TH BLKID 8 "@E2FSPROGS_MONTH@ @E2FSPROGS_YEAR@" "E2fsprogs version @E2FSPROGS_VERSION@"
9.SH NAME
10blkid \- command\-line utility to locate/print block device attributes
11.SH SYNOPSIS
12.B blkid
13[
14.B \-ghlLv
15]
16[
17[
18.B \-c
19.I cachefile
20]
21.B \-w
22.I writecachefile
23]
24[
25.B \-o
26.I format
27]
28[
29.B \-s
30.I tag
31]
32[
33.B \-t
34.IR NAME = value
35]
36[
37.I device ...
38]
39.SH DESCRIPTION
40The
41.B blkid
42program is the command-line interface to working with
43.BR libblkid (3)
44library. It can determine the type of content (e.g. filesystem, swap)
45a block device holds, and also attributes (tokens, NAME=value pairs)
46from the content metadata (e.g. LABEL or UUID fields).
47.PP
48.B blkid
49has two main forms of operation: either searching for a device with a
50specific NAME=value pair, or displaying NAME=value pairs for one or
51more devices.
52.SH OPTIONS
53.TP
54.BI \-c " cachefile"
55Read from
56.I cachefile
57instead of reading from the default cache file
58.IR /etc/blkid.tab .
59If you want to start with a clean cache (i.e. don't report devices previously
60scanned but not necessarily available at this time), specify
61.IR /dev/null .
62.TP
63.B \-g
64Perform a garbage collection pass on the blkid cache to remove
65devices which no longer exist.
66.TP
67.B \-h
68Display a usage message and exit.
69.TP
70.B \-l
71Look up one device that matches the search parameter specified using
72the
73.B \-t
74option. If there are multiple devices that match the specified search
75parameter, then the device with the highest priority is returned, and/or
76the first device found at a given priority. Device types in order of
77decreasing priority are Device Mapper, EVMS, LVM, MD, and finally regular
78block devices. If this option is not specified,
79.B blkid
80will print all of the devices that match the search parameter.
81.TP
82.BI \-o " format"
83Display
84.BR blkid 's
85output using the specified format. The
86.I format
87parameter may be
88.I full
89(the default),
90.I value
91(only print the value of the tags),
92.I list
93(print the devices in a user-friendly format),
94or
95.I device
96(only print the device name).
97.TP
98.B \-L
99Print the devices in a user-friendly list format. This is the
100equivalent of using the option \fB-o list\fR.
101.TP
102.BI \-s " tag"
103For each (specified) device, show only the tags that match
104.IR tag .
105It is possible to specify multiple
106.B \-s
107options. If no tag is specified, then all tokens are shown for all
108(specified) devices.
109In order to just refresh the cache without showing any tokens, use
110.B "-s none"
111with no other options.
112.TP
113.BI \-t " NAME" = "value"
114Search for block devices with tokens named
115.I NAME
116that have the value
117.IR value ,
118and display any devices which are found.
119Common values for
120.I NAME
121include
122.BR TYPE ,
123.BR LABEL ,
124and
125.BR UUID .
126If there are no devices specified on the command line, all block devices
127will be searched; otherwise only the specified devices are searched.
128.TP
129.B \-v
130Display version number and exit.
131.TP
132.BI \-w " writecachefile"
133Write the device cache to
134.I writecachefile
135instead of writing it to the default cache file
136.IR /etc/blkid.tab .
137If you don't want to save the cache to the default file, specify
138.IR /dev/null.
139If not specified it will be the same file as that given by the
140.B \-c
141option.
142.TP
143.I device
144Display tokens from only the specified device. It is possible to
145give multiple
146.I device
147options on the command line. If none is given, all devices which
148appear in
149.I /proc/partitions
150are shown, if they are recognized.
151.SH "RETURN CODE"
152If the specified token was found, or if any tags were shown from (specified)
153devices, 0 is returned. If the specified token was not found, or no
154(specified) devices could be identified, an exit code of 2 is returned.
155For usage or other errors, an exit code of 4 is returned.
156.SH AUTHOR
157.B blkid
158was written by Andreas Dilger for libblkid.
159.SH AVAILABILITY
160.B blkid
161is part the e2fsprogs package since version 1.26 and is available from
162http://e2fsprogs.sourceforge.net.
163.SH "SEE ALSO"
164.BR libblkid (3)