fsck man page on Ultrix

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fsck(8)								       fsck(8)

       fsck - check and repair file system

       /etc/fsck [ -p -P ] [ filesystem ...  ]
       /etc/fsck [ -b block ] [ -y ] [ -n ] [ filesystem ] ...

       The  command  checks and corrects either a standard set of file systems
       or the specified file systems for consistency.  This  command  is  nor‐
       mally  used in the script during automatic reboot.  In this case, reads
       the file to determine which UFS file systems to	check.	 It  uses  the
       information to inspect groups of disks in parallel, taking advantage of
       I/O overlap to check the file systems as quickly as possible.

       The command makes a number of passes to check the file systems for con‐
       sistency.   Usually,  the  root file system is checked on pass 1, other
       root file systems such as partition are checked on pass	2,  and	 other
       small  file  systems  are checked on separate passes.  For example, the
       file systems are usually checked on pass 3 and  the  file  systems  are
       usually	checked	 on  pass  4.  The large user file systems are usually
       checked on the final pass.  A pass number of 0 in causes a disk to  not
       be  checked.   Similarly,  partitions  that are not shown to be mounted
       with or are not checked.

       The option should be used to check file systems.	 The generic file sys‐
       tem  interface,	causes	to  realize  when  a  file system is unmounted
       cleanly and thus prevents from  doing  the  check.   File  systems  are
       unmounted  cleanly  only when an error-free shutdown has been performed
       or the file system was unmounted.  However, a timeout factor is used by
       to  determine  if  should  be  run regardless of the value of the clean
       byte.  The timeout factor is initially set to  20  and  is  decremented
       when any one of three events occur:

	      -	 A file system is mounted,

	      -	 10,000 updates have occurred

	      -	 A  file  system  was  updated	and occurred more than 60 days

       When the timeout factor reaches 0, will automatically check  it.	  This
       factor  can be changed with If the option is used, the parallel consis‐
       tency checks are performed like the option regardless of how  the  file
       system was unmounted.

       If  an  attempt	is made to check a mounted file system using the block
       device, will report filesystem: and will check the filesystem as if the
       option is selected.

       The  system  ensures that only a restricted class of file system incon‐
       sistencies can occur unless hardware or	software  failures  intervene.
       The inconsistencies are limited to:

	      Unreferenced inodes

	      Link counts in inodes are too large

	      Missing blocks in the free list

	      Blocks in the free list are also in files

	      Counts in the superblock are wrong

       These  are  the	only  inconsistencies that corrects with either the or
       option.	If encounters other inconsistencies, it exits with an abnormal
       return  status  and  an automatic reboot will then fail.	 For each cor‐
       rected inconsistency one or more lines are printed identifying the file
       system  on  which  the correction will take place and the nature of the
       correction.  If any inconsistencies occur, the message is  printed  and
       runs  again  to	verify	that the appropriate changes were made.	 After
       correcting a file system, prints the number of files on that file  sys‐
       tem  and	 the  number  of  used and free blocks and also the percent of
       fragments vs blocks.  When the fragmentation exceeds 5%	it  is	recom‐
       mended  that  the file system be dumped to tape, and restored.  Also, a
       clean byte is set for the checked file system.  The root file system is
       checked regardless of whether the clean byte is set.

       Without	the  or options, audits and interactively repairs inconsistent
       conditions for file systems.  If the file system is  inconsistent,  the
       operator is prompted before each correction is attempted.  It should be
       noted that a number of the corrective actions  which  are  not  fixable
       using  the or options will result in some loss of data.	The amount and
       severity of data lost may be determined	from  the  diagnostic  output.
       The  default  action for each consistency correction is to wait for the
       operator to respond or If the operator does not have write  permission,
       defaults to a action.

       If  no file systems are given to then a default list of file systems is
       read from the file The command only checks file systems of type UFS.

       The command checks for the following inconsistencies:

	      Blocks claimed by more than one inode or the free list.

	      Blocks claimed by an inode or the free list outside the range of
	      the file system.

	      Incorrect link counts.

	      Size checks; directory size not of proper format.

	      Bad inode format.

	      Blocks not accounted for.

	      Directory checks; file pointing to unallocated inode; inode num‐
	      ber out of range.

	      Superblock checks; more blocks for inodes than there are in  the
	      file system.

	      Bad free block list format.

	      Total free block or free inode count incorrect.

       If detects allocated but unreferenced files and directories, it prompts
       you before placing them in the directory.  The only restriction is that
       the  directory  must exist in the root of the file system being checked
       and must have empty slots before is run.	 If necessary,	the  directory
       can be enlarged by creating many files in the directory and then remov‐
       ing them.

       General users can run on file systems with certain  restrictions.   The
       user must have execute permissions on the device and general users can‐
       not run on a mounted file system.

       -b     Use the block  specified	immediately  after  the	 flag  as  the
	      superblock for the file system.  Block 32 is always an alternate

       -y     Assume a response to all questions asked by this should be  used
	      with caution as this allows to continue after essentially unlim‐
	      ited trouble has been encountered.

       -n     Assume a response to all questions asked by do not open the file
	      system for writing.

       -p     Check a file system that was not unmounted cleanly.

       -P     Check a file system regardless of how it was unmounted.

       Inode numbers for and in each directory should be checked for validity.
       The command will not allow checking a raw device if the block device is

       Contains default list of file systems to check

See Also
       getmnt(2),   fstab(5),  ufs(5),	crash(8v),  mkfs(8),  mklost+found(8),
       mount(8), mount(8ufs), newfs(8), reboot(8), tunefs(8)


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