.\" Copyright (c) 1980 Regents of the University of California.
.\" All rights reserved. The Berkeley software License Agreement
.\" specifies the terms and conditions for redistribution.
.\" @(#)fsck.8 6.2 (Berkeley) %G%
fsck \- file system consistency check and interactive repair
preens a standard set of filesystems or the specified file systems.
It is normally used in the script
to determine which file systems to check.
It uses the information there to inspect groups of disks in parallel taking
maximum advantage of i/o overlap to check the file systems
Normally, the root file system will be checked on pass 1, other
``root'' (``a'' partition) file systems on pass 2, other
small file systems on separate passes (e.g. the ``d'' file systems
on pass 3 and the ``e'' file systems on pass 4), and finally
the large user file systems on the last pass, e.g. pass 5.
Only partitions in fstab that are mounted ``rw'' or ``rq''
and that have non-zero pass number are checked.
The system takes care that only a restricted class of innocuous
inconsistencies can happen unless hardware or software failures intervene.
These are limited to the following:
Link counts in inodes too large
Missing blocks in the free list
Blocks in the free list also in files
Counts in the super-block wrong
These are the only inconsistencies that
option will correct; if it encounters other inconsistencies, it exits
with an abnormal return status and an automatic reboot will then fail.
For each corrected inconsistency one or more lines will be printed
identifying the file system on which the correction will take place,
and the nature of the correction. After successfully correcting a file
will print the number of files on that file system,
the number of used and free blocks,
and the percentage of fragmentation.
will finish the file system checks, then exit with an abnormal
return status that causes the automatic reboot to fail.
This is useful when you wish to finish the file system checks,
but do not want the machine to come up multiuser.
audits and interactively repairs inconsistent conditions for file systems.
If the file system is inconsistent the operator is prompted for concurrence
before each correction is attempted.
It should be noted that some of the corrective actions which are not
option will result in some loss of data.
The amount and severity of data lost may be determined from the diagnostic
The default action for each consistency correction
is to wait for the operator to respond \fByes\fP or \fBno\fP.
If the operator does not have write permission on the file system
has more consistency checks than
.IR "check, dcheck, fcheck, " "and" " icheck"
The following flags are interpreted by
Use the block specified immediately after the flag as
the super block for the file system. Block 32 is always
an alternate super block.
Assume a yes response to all questions asked by
this should be used with great caution as this is a free license
to continue after essentially unlimited trouble has been encountered.
Assume a no response to all questions asked by
do not open the file system for writing.
If no filesystems are given to
then a default list of file systems is read from
Inconsistencies checked are as follows:
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.
Directory size not of proper format.
Blocks not accounted for anywhere.
File pointing to unallocated inode.
Inode number out of range.
More blocks for inodes than there are in the file system.
Bad free block list format.
Total free block and/or free inode count incorrect.
Orphaned files and directories (allocated but unreferenced) are,
with the operator's concurrence, reconnected by
The name assigned is the inode number.
directory does not exist, it is created.
If there is insufficient space its size is increased.
Checking the raw device is almost always faster.
contains default list of file systems to check.
The diagnostics produced by
are fully enumerated and explained in Appendix A of
``Fsck \- The UNIX File System Check Program'' (SMM:5).
There should be some way to start a \fBfsck \-p\fR at pass \fIn\fR.