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E2UNDO(8)                   System Manager's Manual                  E2UNDO(8)
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 filesys-
       tem 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 AT linux.com)
AVAILABILITY
       e2undo  is  part  of  the  e2fsprogs  package  and  is  available  from
       http://e2fsprogs.sourceforge.net.
SEE ALSO
       mke2fs(8), tune2fs(8)
E2fsprogs version 1.45.6          March 2020                         E2UNDO(8)