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    Command:

    e2fsck

    
    
    

    SYNOPSIS

           e2fsck  [  -pacnyrdfkvtDFV ] [ -b superblock ] [ -B blocksize ] [ -l|-L
           bad_blocks_file  ]  [  -C  fd  ]  [  -j   external-journal   ]   [   -E
           extended_options ] device
    
    
    

    DESCRIPTION

           e2fsck is used to check the ext2/ext3/ext4 family of file systems.  For
           ext3 and ext4 filesystems that use a journal, if the  system  has  been
           shut  down  uncleanly without any errors, normally, after replaying the
           committed transactions  in the  journal,  the  file  system  should  be
           marked  as clean.   Hence, for filesystems that use journalling, e2fsck
           will normally replay the journal and exit, unless its superblock  indi-
           cates that further checking is required.
    
           device  is  the  device  file  where  the  filesystem  is  stored (e.g.
           /dev/hdc1).
    
           Note that in general it is not safe to run e2fsck on  mounted  filesys-
           tems.  The only exception is if the -n option is specified, and -c, -l,
           or -L options are not specified.   However, even if it is  safe  to  do
           so,  the  results  printed by e2fsck are not valid if the filesystem is
           mounted.   If e2fsck asks whether or not you should check a  filesystem
           which  is mounted, the only correct answer is ''no''.  Only experts who
           really know what they are doing should consider answering this question
           in any other way.
    
    
    

    OPTIONS

           -a     This  option  does  the same thing as the -p option.  It is pro-
                  vided for backwards compatibility only;  it  is  suggested  that
                  people use -p option whenever possible.
    
           -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 loca-
                  tion 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 spec-
                  ifies blocksize of the filesystem must be specified in order for
                  the superblock locations that are printed out to be accurate.
    
                  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 check.
    
    
           -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  number
                  is  negative, then absolute value of the file descriptor will be
                  used, and the progress information will be suppressed initially.
                  It  can later be enabled by sending the e2fsck process a SIGUSR1
                  signal.  If the file descriptor  specified  is  0,  e2fsck  will
                  print  a  completion  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 supports directory indexing,  or by  sorting  and
                  compressing directories for smaller directories, or for filesys-
                  tems using traditional linear directories.
    
                  Even without the -D option, e2fsck may sometimes optimize a  few
                  directories  ---  for  example, if directory indexing is enabled
                  and a directory is not indexed  and  would  benefit  from  being
                  indexed, or if the index structures are corrupted and need to be
                  rebuilt.  The -D option forces all directories in the filesystem
                  to  be optimized.  This can sometimes make them a little smaller
                  and slightly faster to  search,  but  in  practice,  you  should
                  rarely need to use this option.
    
                  The -D option will detect directory entries with duplicate names
                  in a single directory, which e2fsck normally  does  not  enforce
                  for performance reasons.
    
           -E extended_options
                  Set  e2fsck  extended options.  Extended options are comma sepa-
                  rated, and may take an argument using  the  equals  ('=')  sign.
                  The following options are supported:
    
                       ea_ver=extended_attribute_version
                              Set  the  version  of  the extended attribute blocks
                              which  e2fsck  will  require  while   checking   the
                              filesystem.   The version number may be 1 or 2.  The
                              default extended attribute version format is 2.
    
                       fragcheck
                              During pass 1, print a detailed report of  any  dis-
                              contiguous blocks for files in the filesystem.
    
                       discard
                              Attempt  to  discard  free  blocks  and unused inode
                              blocks after the full filesystem  check  (discarding
    
           -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.
    
           -k     When combined with the -c option, any existing bad blocks in the
                  bad  blocks  list are preserved, and any new bad blocks found by
                  running badblocks(8) will be added to the  existing  bad  blocks
                  list.
    
           -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 numbers are based on  the  blocksize  of  the  filesystem.
                  Hence,  badblocks(8) must be given the blocksize of the filesys-
                  tem 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
                  program.
    
           -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.
                  This option may not be specified at the same time as the  -p  or
                  -y options.
    
           -p     Automatically  repair  ("preen")  the  file system.  This option
                  will cause e2fsck to automatically fix any  filesystem  problems
                  that  can be safely fixed without human intervention.  If e2fsck
                  discovers a problem which may require the  system  administrator
                  to  take  additional  corrective  action,  e2fsck  will  print a
                  description of the problem and then exit with the value 4  logi-
                  cally  or'ed  into  the exit code.  (See the EXIT CODE section.)
                  This option is normally used by the system's boot  scripts.   It
                  may not be specified at the same time as the -n or -y options.
    
           -r     This  option  does nothing at all; it is provided only for back-
                  wards compatibility.
    
           -t     Print timing statistics for e2fsck.   If  this  option  is  used
                  twice,  additional  timing  statistics  are printed on a pass by
                  pass basis.
    
                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
    
    
    

    SIGNALS

           The following signals have the following effect when sent to e2fsck.
    
           SIGUSR1
                  This  signal  causes e2fsck to start displaying a completion bar
                  or emitting progress information.  (See  discussion  of  the  -C
                  option.)
    
           SIGUSR2
                  This signal causes e2fsck to stop displaying a completion bar or
                  emitting progress information.
    
    
    

    REPORTING BUGS

           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.   (Make  sure  the  messages
           printed by e2fsck are in English; if your system has been configured so
           that e2fsck's messages have  been  translated  into  another  language,
           please  set  the the LC_ALL environment variable to C so that the tran-
           script of e2fsck's output will  be  useful  to  me.)   If  you  have  a
           writable  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 trouble, try running the
           debugfs(8) command and send the output 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 uuencode(1).  The
           most useful data you can send to help reproduce the bug is a compressed
           raw  image dump of the filesystem, generated using e2image(8).  See the
           e2image(8) man page for more details.
    
           Always include the full version string which e2fsck displays when it is
           run, so I know which version you are running.
    
    
    

    AUTHOR

           This version of e2fsck was written by Theodore Ts'o <tytso@mit.edu>.
    
    
    

    SEE ALSO

    
    
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