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.

SEE ALSO

       mke2fs(8), tune2fs(8)