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RedHat 9 (Linux i386) - man page for fsck (redhat section 8)

FSCK(8) 			     System Manager's Manual				  FSCK(8)

       fsck - check and repair a Linux file system

       fsck [ -sACVRTNP ] [ -t fstype ] [filesys ... ] [--] [ fs-specific-options ]

       fsck  is  used to check and optionally repair one or more Linux file systems.  filesys can
       be a device name (e.g.  /dev/hdc1, /dev/sdb2), a mount point (e.g.  /, /usr, /home), or an
       ext2   label   or   UUID  specifier  (e.g.   UUID=8868abf6-88c5-4a83-98b8-bfc24057f7bd  or
       LABEL=root).  Normally, the fsck program will try to run filesystems on different physical
       disk drives in parallel to reduce total amount time to check all of the filesystems.

       If  no  filesystems are specified on the command line, and the -A option is not specified,
       fsck will default to checking filesystems in /etc/fstab serial.	This is equivalent to the
       -As options.

       The exit code returned by fsck is the sum of the following conditions:
	    0	 - No errors
	    1	 - File system errors corrected
	    2	 - System should be rebooted
	    4	 - File system errors left uncorrected
	    8	 - Operational error
	    16	 - Usage or syntax error
	    32	 - Fsck canceled by user request
	    128  - Shared library error
       The  exit  code	returned when multiple file systems are checked is the bit-wise OR of the
       exit codes for each file system that is checked.

       In  actuality,  fsck  is  simply  a  front-end  for  the  various  file	system	 checkers
       (fsck.fstype)  available under Linux.  The file system-specific checker is searched for in
       /sbin first, then in /etc/fs and /etc, and finally in the directories listed in	the  PATH
       environment  variable.	Please see the file system-specific checker manual pages for fur-
       ther details.

       -s     Serialize fsck operations.  This is a  good  idea  if  you  are  checking  multiple
	      filesystems  and the checkers are in an interactive mode.  (Note: e2fsck(8) runs in
	      an interactive mode by default.  To make e2fsck(8) run in a  non-interactive  mode,
	      you must either specify the -p or -a option, if you wish for errors to be corrected
	      automatically, or the -n option if you do not.)

       -t fslist
	      Specifies the type(s) of file system to be checked.  When the -A flag is specified,
	      only  filesystems  that match fslist are checked.  The fslist parameter is a comma-
	      separated list of filesystems and options specifiers.  All of  the  filesystems  in
	      this comma-separated list may be prefixed by a negation operator 'no' or '!', which
	      requests that only those filesystems not listed in fslist will be checked.  If  all
	      of  the  filesystems  in	fslist are not prefixed by a negation operator, then only
	      those filesystems listed in fslist will be checked.

	      Options specifiers may be included in the comma separated fslist.  They  must  have
	      the  format opts=fs-option.  If an options specifier is present, then only filesys-
	      tems which contain fs-option in their mount options field  of  /etc/fstab  will  be
	      checked.	 If  the  options specifier is prefixed by a negation operator, then only
	      those filesystems that do not have  fs-option  in  their	mount  options	field  of
	      /etc/fstab will be checked.

	      For  example,  if  opts=ro  appears  in  fslist,	then  only  filesystems listed in
	      /etc/fstab with the ro option will be checked.

	      For compatibility with Mandrake distributions whose boot	scripts  depend  upon  an
	      unauthorized  UI	change to the fsck program, if a filesystem type of loop is found
	      in fslist, it is treated as if opts=loop were specified as an argument  to  the  -t

	      Normally, the filesystem type is deduced by searching for filesys in the /etc/fstab
	      file and using the corresponding entry.  If the type can not be deduced, and  there
	      is  only	a  single filesystem given as an argument to the -t option, fsck will use
	      the specified filesystem type.  If this type is not  available,  then  the  default
	      file system type (currently ext2) is used.

       -A     Walk  through  the  /etc/fstab  file  and try to check all file systems in one run.
	      This option is typically used from the /etc/rc system initalization  file,  instead
	      of multiple commands for checking a single file system.

	      The  root  filesystem  will be checked first unless the -P option is specified (see
	      below).  After that, filesystems will be checked in  the	order  specified  by  the
	      fs_passno  (the  sixth) field in the /etc/fstab file.  Filesystems with a fs_passno
	      value of 0 are skipped and are not checked at all.  Filesystems  with  a	fs_passno
	      value of greater than zero will be checked in order, with filesystems with the low-
	      est fs_passno number being checked first.  If there are multiple	filesystems  with
	      the same pass number, fsck will attempt to check them in parallel, although it will
	      avoid running multiple filesystem checks on the same physical disk.

	      Hence, a very common configuration in /etc/fstab files is to set the root  filesys-
	      tem  to  have a fs_passno value of 1 and to set all filesystems to have a fs_passno
	      value of 2.  This will allow fsck to automatically run filesystem checkers in  par-
	      allel  if  it  is advantageous to do so.	System administrators might choose not to
	      use this configuration if they need to avoid multiple filesystem checks running  in
	      parallel	for  some  reason --- for example, if the machine in question is short on
	      memory so that excessive paging is a concern.

       -C     Display completion/progress bars for those filesystems checkers (currently only for
	      ext2)  which  support them.   Fsck will manage the filesystem checkers so that only
	      one of them will display a progress bar at a time.

       -N     Don't execute, just show what would be done.

       -P     When the -A flag is set, check the root  filesystem  in  parallel  with  the  other
	      filesystems.   This  is  not the safest thing in the world to do, since if the root
	      filesystem is in doubt things like the e2fsck(8)	executable  might  be  corrupted!
	      This  option  is	mainly provided for those sysadmins who don't want to repartition
	      the root filesystem to be small and compact (which is really the right solution).

       -R     When checking all file systems with the -A flag, skip the root file system (in case
	      it's already mounted read-write).

       -T     Don't show the title on startup.

       -V     Produce  verbose	output, including all file system-specific commands that are exe-

	      Options which are not understood by fsck	are  passed  to  the  filesystem-specific
	      checker.	 These	arguments must not take arguments, as there is no way for fsck to
	      be able to properly guess which arguments take options and which don't.

	      Options and arguments which follow the  --  are  treated	as  file  system-specific
	      options to be passed to the file system-specific checker.

	      Please  note  that  fsck is not designed to pass arbitrarily complicated options to
	      filesystem-specific checkers.  If you're doing something complicated,  please  just
	      execute  the  filesystem-specific checker directly.  If you pass fsck some horribly
	      complicated option and arguments, and it doesn't do what you expect,  don't  bother
	      reporting  it as a bug.  You're almost certainly doing something that you shouldn't
	      be doing with fsck.

       Currently, standardized file system-specific options are somewhat in flux.   Although  not
       guaranteed, the following options are supported by most file system checkers:

       -a     Automatically  repair  the  file system without any questions (use this option with
	      caution).  Note that e2fsck(8) supports -a for backwards compatibility only.   This
	      option  is  mapped to e2fsck's -p option which is safe to use, unlike the -a option
	      that most file system checkers support.

       -r     Interactively repair the filesystem (ask for confirmations).  Note: It is generally
	      a  bad  idea to use this option if multiple fsck's are being run in parallel.  Also
	      note that this is e2fsck's default behavior; it supports this option for	backwards
	      compatibility reasons only.

       Theodore Ts'o (tytso@mit.edu)


       The fsck program's behavior is affected by the following environment variables:

	      If  this environment variable is set, fsck will attempt to run all of the specified
	      filesystems in parallel, regardless of whether the filesystems appear to be on  the
	      same  device.  (This is useful for RAID systems or high-end storage systems such as
	      those sold by companies such as IBM or EMC.)

	      This environment variable will limit the maximum number  of  file  system  checkers
	      that  can  be  running  at one time.  This allows configurations which have a large
	      number of disks to avoid fsck starting too many file system checkers at once, which
	      might  overload CPU and memory resources available on the system.  If this value is
	      zero, then an unlimited number of processes can be spawned.  This is currently  the
	      default,	but  future  versions  of fsck may attempt to automatically determine how
	      many file system checks can be run based on  gathering  accounting  data	from  the
	      operating system.

       PATH   The  PATH environment variable is used to find file system checkers.  A set of sys-
	      tem directories are searched first: /sbin, /sbin/fs.d, /sbin/fs, /etc/fs, and /etc.
	      Then the set of directories found in the PATH environment are searched.

	      This  environment variable allows the system administrator to override the standard
	      location of the /etc/fstab file.	It is also use for  developers	who  are  testing

       fstab(5), mkfs(8), fsck.minix(8), fsck.ext2(8) or e2fsck(8), fsck.xiafs(8).

E2fsprogs version 1.32			  November 2002 				  FSCK(8)

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