1E2UNDO(8)                   System Manager's Manual                  E2UNDO(8)
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NAME

6       e2undo - Replay an undo log for an ext2/ext3/ext4 file system
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SYNOPSIS

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

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

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

47       e2undo   was    written    by    Aneesh    Kumar    K.V.    (aneesh.ku‐
48       mar@linux.vnet.ibm.com)
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AVAILABILITY

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

55       mke2fs(8), tune2fs(8)
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60E2fsprogs version 1.46.5         December 2021                       E2UNDO(8)
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