Section: User Commands (1)
udfinfo --- show information about UDF filesystem
udfinfo [ options ] device
shows various information about a UDF filesystem stored either on
the block device or in the disk file image. The output from the udfinfo
suitable for parsing by external applications or scripts.
Display the usage and the list of options.
- -b,--blocksize= block-size
Specify the size of blocks in bytes. Valid block size for a UDF filesystem is
a power of two in the range from 512 to 32768 and must match a
device logical (sector) size. If omitted, udfinfo tries to autodetect
block size. First it tries logical (sector) size and then all valid block sizes.
- --vatblock= vat-block
Specify the block location of the Virtual Allocation Table. Virtual Allocation
Table is present only on UDF disks with Virtual Partition Map and must be at the
last written/recorded disk block.
If omitted, udfinfo for optical disc tries to detect the last recorded
block with fallback to the last block of block device or disk file image. In
most cases, this fallback does not have to work and for disk file images with
Virtual Allocation Table is necessary to specify the correct location.
Virtual Allocation Table contains locations of UDF disk blocks needed to read
data storage, determinate used and free space blocks, read File Set Identifier
and calculate Windows-specific Volume Serial Number. Also, it contains Logical
Volume Identifier and overwrite previously stored in Logical Volume Descriptor.
Encode UDF string identifiers on output according to current locale settings
Encode UDF string identifiers on output to 8-bit OSTA Compressed Unicode format,
equivalent to Latin1 (ISO-8859-1). This will work only for strings which Unicode
code points are below U+100.
Encode UDF string identifiers on output to 16-bit OSTA Compressed Unicode
format, equivalent to UCS-2BE.
Encode UDF string identifiers on output to UTF-8.
returns 0 if successful, non-zero if there are problems like a
block device does not contain UDF filesystem.
First part of the udfinfo
standard output contains information in
format. List of all keys with their meaning are in the
File name of the selected block device or disk file image
label is an alias for lvid, see udflabel(8) section
UDF LABEL AND UUID
UUID are first 16 hexadecimal lowercase digits of fullvsid, but see
udflabel(8) section UDF LABEL AND UUID
UDF Logical Volume Identifier stored in UDF Logical Volume Descriptor
UDF Volume Identifier stored in UDF Primary Volume Descriptor
fullvsid after uuid part, typically 17.-127. character
UDF File Set Identifier stored in UDF File Set Descriptor
UDF Volume Set Identifier stored in UDF Primary Volume Descriptor
Windows-specific Volume Serial Number
UDF block size
Number of all blocks on the selected block device or disk file image
Number of used space blocks on UDF disk for data storage
Number of free space blocks on UDF disk for data storage
Number of blocks which are behind the last block used by UDF disk
Number of stored files on UDF disk
Number of stored directories on UDF disk
UDF revision needed for reading UDF disk
UDF revision needed for writing or modifying UDF disk
UDF block location of the Virtual Allocation Table (visible only when available)
UDF integrity of Logical Volume, one of: opened, closed,
UDF Access Type, one of: overwritable, rewritable, writeonce,
readonly, pseudo-overwritable, unknown
When UDF integrity is not closed it means that the UDF disk was not
properly unmounted, is in an inconsistent state and needs repairing.
All UDF string identifiers are stored on UDF disk in Unicode, therefore they are
locale or code page agnostic. Options --locale, --u8,
--u16 and --utf8 controls how are identifiers encoded on output.
All newline characters from the UDF string identifiers are removed, so it is
guaranteed that the newline character is present only as a separator.
Second part of the udfinfo standard output contains list of UDF block
types stored on device, one per line in the following format:
start=block-num, blocks=block-count, type=block-type
With meaning that block-type starts at UDF block block-num and
span block-count blocks on device.
Windows-specific Volume Serial Number is a non-standard 32-bit checksum,
calculated as four separate 8-bit XOR checksums of 512 bytes long UDF File Set
Descriptor. Therefore, it cannot be set or changed as opposed to UUID which is
64-bit long. This non-standard checksum is used only by Windows systems
(since Windows 98 era when it was introduced) and can be displayed on Windows
systems by applications like vol, dir or fsutil.exe.
is not able to read Metadata Partition yet. Therefore, determining
used and free space blocks, reading File Set Identifier and calculating
Windows-specific Volume Serial Number may not be available for disks with UDF
revisions higher than 2.01 which have Metadata Partition.
udfinfo prior to version 2.1 was unable to read Virtual Allocation Table
stored outside of Information Control Block. Therefore above limitation applied
also for some Write Once media.
Pali Rohár <firstname.lastname@example.org>
is part of the udftools package since version 2.0 and is available