Provided by: e2fsprogs_1.42.9-3ubuntu1_amd64
dumpe2fs - dump ext2/ext3/ext4 filesystem information
dumpe2fs [ -bfhixV ] [ -o superblock=superblock ] [ -o blocksize=blocksize ] device
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.
-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.
You need to know the physical filesystem structure to understand the output.
dumpe2fs was written by Remy Card <Remy.Card@linux.org>. It is currently being maintained by Theodore Ts'o <firstname.lastname@example.org>.
dumpe2fs is part of the e2fsprogs package and is available from http://e2fsprogs.sourceforge.net.