.TH FSCK 1
.SH NAME
fsck \- perform file system consistency check
.SH SYNOPSIS
\fBfsck\fP [\fB\-pfwcyn\fP] [\fB\-l\fP \fInumber\fP] [\fIfilesystem\fP ...]
.SH DESCRIPTION
.B Fsck
checks a file system's consistency after a crash
or to make sure that an unknown file system may be safely mounted.
.PP
.B Fsck
is really a forerunner to
.B fsck1
through
.BR fsck2f ,
see
.BR fsck1 (1)
for more details.
.PP
This program is a kind of manager to the four real checkers, it will read
/etc/fstab (see
.BR fstab (5))
to check all the file systems with a non-zero pass number if no arguments are
given, or it will use the fstab to translate the name of a mount point to the
proper device, so you can type
.B fsck /usr
for instance.  It will know which program to call by looking at the superblock
type.
.SS "The clean flag"
.B Fsck
is a bit more than just a forerunner, it will also manage the so-called
"file system clean flag".  This flag is cleared by the kernel when a file
system is mounted, and set when it is unmounted or when the system is rebooted
with
.BR reboot (8),
but only if it was set to begin with.
.PP
The clean flag will only be set if it is specifically enabled by a special
magic number in the superblock.  It should only be enabled if the file system
is never ever used by a system that does not know about the clean flag, because
those systems will either choke on it (most likely), or not clear it on mount.
.PP
.B Mkfs
will enable the clean flag when making a flex file system, because no other
system can use this file system type anyway.
.SH OPTIONS
.TP
.B \-p
Run in preen mode repairing noncritical errors automatically.  Errors that
need operator intervention are only noted, but not repaired.  Even file
systems that are mounted are checked, because the root file system is mounted
read-only at boot time.  You should reboot immediately if the root file
system had to be repaired.  Several fsck's should be run in parallel for file
systems with the same pass number, but this is not yet implemented.  (The
output from the different fsck's would make an unintelligible mess.)
.TP
\fB\-l\fP \fInumber\fP
Limit the number of fscks run in parallel in preen mode.  (Useful, isn't it?)
.TP
.B \-f
Force checking even if the file system is marked clean.
.TP
.B \-w
Only check file systems from fstab that are normally mounted read-write.
.TP
.B \-c
Toggle the clean flag enable.  On a file system with a clean flag it will
disable the flag and reset it, on a file system without the clean flag enabled
it will write the necessary magic number to enable it.  No check will be done,
all other options will be ignored.
.TP
.B \-n
Assume 'no' to all questions asked, the file system will be opened read-only
and only a report on all the errors will be generated.
.B Fsck
will automatically revert to this mode if the file system can't be opened
read-write.
.TP
.B \-y
Assume 'yes' on all questions asked.  This is a dangerous option, because
it will allow repairs being made without user supervision.  Better first
run
.B fsck -n
to see what it is up to.
.SH FILES
.TP 15
.B /etc/fstab
Default list of file systems to check.
.TP
.B /etc/mtab
To check if a file system is currently mounted.
.SH "SEE ALSO"
.BR fsck1 (1),
.BR fstab (5),
.BR mkfs (1),
.BR mount (1).
.SH "EXIT STATUS"
.TP 5
.B 0
Either there were no errors, or all errors were successfully corrected.
.TP
.B 2
A
.B QUIT
signal has been typed while in preen mode.  The fsck is finished, but the
reboot must be interrupted.
.TP
.B 4
Errors have been corrected on a mounted file system.
.TP
.B 8
There are serious errors that have not been fixed, or another severe error.
.TP
.B 12
An
.B INTERRUPT
signal stopped the fsck.
.SH DIAGNOSTICS
The message you like to see at boot time: "/dev/hd3: is clean".
.SH AUTHOR
Kees J. Bot (kjb@cs.vu.nl)
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.\" $PchId: fsck.1,v 1.3 1995/11/27 22:12:25 philip Exp $