E2UNDO

Section: Maintenance Commands (8)
Updated: March 2020
Page Index

NAME

e2undo - Replay an undo log for an ext2/ext3/ext4 filesystem

SYNOPSIS

e2undo [ -f ] [ -h ] [ -n ] [ -o offset ] [ -v ] [ -z undo_file ] undo_log device

DESCRIPTION

e2undo will replay the undo log undo_log for an ext2/ext3/ext4 filesystem found on device. This can be used to undo a failed operation by an e2fsprogs program.

OPTIONS

-f: Normally, e2undo will check the filesystem superblock to make sure the undo log matches with the filesystem on the device. If they do not match, e2undo will refuse to apply the undo log as a safety mechanism. The -f option disables this safety mechanism.
-h: Display a usage message.
-n: Dry-run; do not actually write blocks back to the filesystem.
-o offset: Specify the filesystem's offset (in bytes) from the beginning of the device or file.
-v: Report which block we're currently replaying.
-z undo_file: Before overwriting a file system block, write the old contents of the block to an undo file. This undo file can be used with e2undo(8) to restore the old contents of the file system should something go wrong. If the empty string is passed as the undo_file argument, the undo file will be written to a file named e2undo-device.e2undo in the directory specified via the E2FSPROGS_UNDO_DIR environment variable.
WARNING: The undo file cannot be used to recover from a power or system crash.

AUTHOR

e2undo was written by Aneesh Kumar K.V. (aneesh.kumar@linux.vnet.ibm.com)

AVAILABILITY

e2undo is part of the e2fsprogs package and is available from http://e2fsprogs.sourceforge.net.