What does the command dumpe2fs H do?

The "dumpe2fs" command is used to display information about ext2, ext3 and ext4 filesystems. dumpe2fs displays superblock and block group information for filesystems present on a device.

Syntax: dumpe2fs [ -bfhixV ] [ -o superblock=superblock ] [ -o blocksize=blocksize ] device

Options -b print the blocks which are reserved as bad in the filesystem. -o superblock=superblock use the block superblock when examining the filesystem. This option is not usually needed except by a filesystem wizard who is examining the remains of a very badly cor- rupted filesystem. -o blocksize=blocksize use blocks of blocksize bytes when examining the filesystem. This option is not usu- ally needed except by a filesystem wizard who is examining the remains of a very badly corrupted filesystem. -f force dumpe2fs to display a filesystem even though it may have some filesystem feature flags which dumpe2fs may not understand (and which can cause some of dumpe2fs's display to be suspect). -h only display the superblock information and not any of the block group descriptor detail information. -i display the filesystem data from an image file created by e2image, using device as the pathname to the image file. -x print the detailed group information block numbers in hexadecimal format -V print the version number of dumpe2fs and exit.

dumpe2fs - Example Display Superblock information

# dumpe2fs -h /dev/sda1 dumpe2fs 1.42 (29-Nov-2011) Filesystem volume name: Last mounted on: / Filesystem UUID: 4daba06c-1d4d-4bbc-8f66-0a48cb20d0b4 Filesystem magic number: 0xEF53 Filesystem revision #: 1 (dynamic) Filesystem features: has_journal ext_attr resize_inode dir_index filetype needs_recovery extent flex_bg sparse_super large_file huge_file uninit_bg dir_nlink extra_isize Filesystem flags: signed_directory_hash Default mount options: (none) Filesystem state: clean Errors behavior: Continue Filesystem OS type: Linux Inode count: 9609216 Block count: 38419456 Reserved block count: 1920972 Free blocks: 11195030 Free inodes: 8480522 First block: 0 Block size: 4096 Fragment size: 4096 Reserved GDT blocks: 1014 Blocks per group: 32768 Fragments per group: 32768 Inodes per group: 8192 Inode blocks per group: 512 Flex block group size: 16 Filesystem created: Sat Oct 22 19:36:56 2011 Last mount time: Tue Jul 23 19:57:51 2013 Last write time: Wed Jul 17 12:06:55 2013 Mount count: 6 Maximum mount count: 35 Last checked: Wed Jul 17 12:06:55 2013 Check interval: 15552000 (6 months) Next check after: Mon Jan 13 11:06:55 2014 Lifetime writes: 605 GB Reserved blocks uid: 0 (user root) Reserved blocks gid: 0 (group root) First inode: 11 Inode size: 256 Required extra isize: 28 Desired extra isize: 28 Journal inode: 8 First orphan inode: 6553671 Default directory hash: half_md4 Directory Hash Seed: 0206aa9d-9545-4e90-886e-d76a5511ebc7 Journal backup: inode blocks Journal features: journal_incompat_revoke Journal size: 128M Journal length: 32768 Journal sequence: 0x00242dd8 Journal start: 23267

Section: Maintenance Commands (8)
Updated: August 2014
Index Return to Main Contents


NAME

dumpe2fs - dump ext2/ext3/ext4 filesystem information  

SYNOPSIS

dumpe2fs [ -bfhixV ] [ -o superblock=superblock ] [ -o blocksize=blocksize ] device  

DESCRIPTION

dumpe2fs prints the super block and blocks group information for the filesystem present on device.

Note: When used with a mounted filesystem, the printed information may be old or inconsistent.  

OPTIONS

-b print the blocks which are reserved as bad in the filesystem. -o superblock=superblock use the block superblock when examining the filesystem. This option is not usually needed except by a filesystem wizard who is examining the remains of a very badly corrupted filesystem. -o blocksize=blocksize use blocks of blocksize bytes when examining the filesystem. This option is not usually needed except by a filesystem wizard who is examining the remains of a very badly corrupted filesystem. -f force dumpe2fs to display a filesystem even though it may have some filesystem feature flags which dumpe2fs may not understand (and which can cause some of dumpe2fs's display to be suspect). -h only display the superblock information and not any of the block group descriptor detail information. -i display the filesystem data from an image file created by e2image, using device as the pathname to the image file. -x print the detailed group information block numbers in hexadecimal format -V print the version number of dumpe2fs and exit.

BUGS

You need to know the physical filesystem structure to understand the output.  

AUTHOR

dumpe2fs was written by Remy Card <>. It is currently being maintained by Theodore Ts'o <>.  

AVAILABILITY

dumpe2fs is part of the e2fsprogs package and is available from http://e2fsprogs.sourceforge.net.  

SEE ALSO

e2fsck(8), mke2fs(8), tune2fs(8). ext4(5)


Index

NAMESYNOPSISDESCRIPTIONOPTIONSBUGSAUTHORAVAILABILITYSEE ALSO

Which command is used to display the amount of free space that exists on a file system?

df — Display the amount of free space in the file system.

Which of the following commands can be used to format a disk partition as ext4?

An alternate filesystem may be used by running a different format command. To format the partition using ext4, run the command mkfs. ext4 /dev/vdb1 .

What is the default shell in Linux called?

In most Linux systems, the default shell is bash but we can change that to any other shell-like zsh, fish, sh, and any other.

What command can be used to check different kinds of filesystems on Linux for errors?

What command can be used to check different kinds of filesystems on Linux for errors? - chkdsk.