Appendix B. Manual Page of e2fsck

E2FSCK(8)                                               E2FSCK(8)

       e2fsck - check a Linux second extended file system

       e2fsck  [ -pacnyrdfvstDFSV ] [ -b superblock ] [ -B block­
       size ] [ -l|-L bad_blocks_file ] [ -C fd ] [ -j  external-
       journal ] [ -E extended_options ] device

       e2fsck  is used to check a Linux second extended file sys­
       tem (ext2fs).  E2fsck also supports ext2 filesystems coun­
       taining  a journal, which are also sometimes known as ext3
       filesystems, by first applying the journal to the filesys­
       tem  before  continuing  with  normal  e2fsck  processing.
       After the journal has been applied, a filesystem will nor­
       mally  be  marked  as clean.  Hence, for ext3 filesystems,
       e2fsck will normally run the journal and exit, unless  its
       superblock indicates that further checking is required.

       device  is  the device file where the filesystem is stored
       (e.g.  /dev/hdc1).

       -a     This option does the same thing as the  -p  option.
              It is provided for backwards compatibility only; it
              is suggested that people  use  -p  option  whenever

       -b superblock
              Instead  of  using  the  normal  superblock, use an
              alternative  superblock  specified  by  superblock.
              This  option  is  normally  used  when  the primary
              superblock has been corrupted.  The location of the
              backup  superblock is dependent on the filesystem's
              blocksize.  For filesystems with 1k  blocksizes,  a
              backup  superblock  can be found at block 8193; for
              filesystems with 2k blocksizes, at block 16384; and
              for 4k blocksizes, at block 32768.

              Additional  backup superblocks can be determined by
              using the mke2fs program using  the  -n  option  to
              print out where the superblocks were created.   The
              -b option to mke2fs, which specifies  blocksize  of
              the  filesystem  must be specified in order for the
              superblock locations that are  printed  out  to  be

              If  an  alternative superblock is specified and the
              filesystem is not  opened  read-only,  e2fsck  will
              make  sure  that  the primary superblock is updated
              appropriately upon  completion  of  the  filesystem

       -B blocksize
              Normally,  e2fsck will search for the superblock at
              various different block sizes in an attempt to find
              the  appropriate  block  size.   This search can be
              fooled in some cases.  This option forces e2fsck to
              only  try  locating  the superblock at a particular
              blocksize.  If the superblock is not found,  e2fsck
              will terminate with a fatal error.

       -c     This  option  causes e2fsck to run the badblocks(8)
              program to find any blocks which  are  bad  on  the
              filesystem,  and  then  marks them as bad by adding
              them to the bad block inode.   If  this  option  is
              specified  twice,  then  the bad block scan will be
              done using a non-destructive read-write test.

       -C fd  This  option  causes  e2fsck  to  write  completion
              information  to  the  specified  file descriptor so
              that the progress of the filesystem  check  can  be
              monitored.   This  option is typically used by pro­
              grams  which  are  running  e2fsck.   If  the  file
              descriptor specified is 0, e2fsck will print a com­
              pletion bar as it goes about  its  business.   This
              requires  that e2fsck is running on a video console
              or terminal.

       -d     Print debugging  output  (useless  unless  you  are
              debugging e2fsck).

       -D     Optimize  directories  in  filesystem.  This option
              causes e2fsck to try to optimize  all  directories,
              either  by  reindexing  them if the filesystem sup­
              ports directory indexing,  or by sorting  and  com­
              pressing  directories  for  smaller directories, or
              for filesystems using traditional  linear  directo­

       -E extended_options
              Set  e2fsck extended options.  Extended options are
              comma separated, and may take an argument using the
              equals  ('=') sign.  The following options are sup­

                          Assume  the  format  of  the   extended
                          attribute  blocks  in the filesystem is
                          the specified version number.  The ver­
                          sion number may be 1 or 2.  The default
                          extended attribute version format is 2.

       -f     Force checking even if the file system seems clean.

       -F     Flush the filesystem device's buffer caches  before
              beginning.   Only  really  useful  for doing e2fsck
              time trials.

       -j external-journal
              Set the pathname  where  the  external-journal  for
              this filesystem can be found.

       -l filename
              Add  the block numbers listed in the file specified
              by filename to the list of bad blocks.  The  format
              of  this  file  is the same as the one generated by
              the badblocks(8) program.  Note that the block num­
              bers  are based on the blocksize of the filesystem.
              Hence, badblocks(8) must be given the blocksize  of
              the  filesystem in order to obtain correct results.
              As a result, it is much simpler and  safer  to  use
              the  -c option to e2fsck, since it will assure that
              the correct parameters are passed to the  badblocks

       -L filename
              Set  the  bad  blocks list to be the list of blocks
              specified by filename.  (This option is the same as
              the  -l  option,  except  the  bad  blocks  list is
              cleared before the blocks listed in  the  file  are
              added to the bad blocks list.)

       -n     Open the filesystem read-only, and assume an answer
              of `no' to all questions.  Allows e2fsck to be used
              non-interactively.   (Note:  if  the  -c, -l, or -L
              options are specified in addition to the -n option,
              then  the  filesystem will be opened read-write, to
              permit the bad-blocks list to be updated.  However,
              no other changes will be made to the filesystem.)

       -p     Automatically  repair  ("preen")  the  file  system
              without any questions.

       -r     This option does nothing at  all;  it  is  provided
              only for backwards compatibility.

       -s     This  option  will byte-swap the filesystem so that
              it is using  the  normalized,  standard  byte-order
              (which  is i386 or little endian).  If the filesys­
              tem is already in the standard  byte-order,  e2fsck
              will take no action.

       -S     This  option will byte-swap the filesystem, regard­
              less of its current byte-order.

       -t     Print timing statistics for e2fsck.  If this option
              is  used  twice,  additional  timing statistics are
              printed on a pass by pass basis.

       -v     Verbose mode.

       -V     Print version information and exit.

       -y     Assume an answer of `yes' to all questions;  allows
              e2fsck to be used non-interactively.

       The exit code returned by e2fsck is the sum of the follow­
       ing conditions:
            0    - No errors
            1    - File system errors corrected
            2    - File system errors corrected, system should
                   be rebooted
            4    - File system errors left uncorrected
            8    - Operational error
            16   - Usage or syntax error
            32   - E2fsck canceled by user request
            128  - Shared library error

       The following signals have the following effect when  sent
       to e2fsck.

              This  signal  causes  e2fsck  to start displaying a
              completion bar.  (See discussion of the -C option.)

              This signal causes e2fsck to stop displaying a com­
              pletion bar.

       Almost any piece of  software  will  have  bugs.   If  you
       manage  to find a filesystem which causes e2fsck to crash,
       or which e2fsck is unable to repair, please report  it  to
       the author.

       Please include as much information as possible in your bug
       report.  Ideally, include a  complete  transcript  of  the
       e2fsck  run,  so I can see exactly what error messages are
       displayed.  If you have a writeable filesystem  where  the
       transcript can be stored, the script(1) program is a handy
       way to save the output of e2fsck to a file.

       It is also useful to send the output of dumpe2fs(8).  If a
       specific  inode  or inodes seems to be giving e2fsck trou­
       ble, try running the debugfs(8) command and send the  out­
       put  of the stat(1u) command run on the relevant inode(s).
       If the inode is a directory, the debugfs dump command will
       allow  you to extract the contents of the directory inode,
       which can sent to me after being first run  through  uuen­

       Always  include  the full version string which e2fsck dis­
       plays when it is run, so I know which version you are run­

       This  version  of  e2fsck  was  written  by  Theodore Ts'o

       mke2fs(8), tune2fs(8), dumpe2fs(8), debugfs(8)

E2fsprogs version 1.34      July 2003                   E2FSCK(8)