.\"	$NetBSD: fsck_msdos.8,v 1.18 2016/09/11 04:12:08 sevan Exp $
.\"
.\" Copyright (C) 1995 Wolfgang Solfrank
.\" Copyright (c) 1995 Martin Husemann
.\"
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.\" modification, are permitted provided that the following conditions
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.Dd September 11, 2016
.Dt FSCK_MSDOS 8
.Os
.Sh NAME
.Nm fsck_msdos
.Nd DOS/Windows (FAT) filesystem consistency checker
.Sh SYNOPSIS
.Nm
.Fl p
.Op Fl f
.Ar filesystem ...
.Nm
.Op Fl fny
.Op Fl x Ar snap-backup
.Ar filesystem ...
.Sh DESCRIPTION
The
.Nm
utility verifies and repairs
.Tn FAT
filesystems (more commonly known
as
.Tn DOS
filesystems).
.Pp
The first form of
.Nm
preens the specified filesystems.
It is normally started by
.Xr fsck 8
run from
.Pa /etc/rc
during automatic reboot, when a FAT filesystem is detected.
When preening file systems,
.Nm
will fix common inconsistencies non-interactively.
If more serious problems are found,
.Nm
does not try to fix them, indicates that it was not
successful, and exits.
.Pp
The second form of
.Nm
checks the specified file systems and tries to repair all
detected inconsistencies, requesting confirmation before
making any changes.
.Pp
The options are as follows:
.Bl -tag -width XxXsnapXbackupXX
.It Fl f
This option is ignored by
.Nm ,
and is present only for compatibility with programs that
check other file system types for consistency, such as
.Xr fsck_ffs 8 .
.It Fl n
Causes
.Nm
to assume no as the answer to all operator
questions, except
.Dq CONTINUE? .
.It Fl p
Preen the specified filesystems.
.It Fl x Ar snap-backup
Use a snapshot with
.Ar snap-backup
as backup to check a read-write mounted filesystem.
Must be used with
.Fl n .
See
.Xr fss 4
for more details.
The point is to check an internally-consistent version of the
filesystem to find out if it is damaged; on failure one should unmount
the filesystem and repair it.
.It Fl y
Causes
.Nm
to assume yes as the answer to all operator questions.
.El
.Sh SEE ALSO
.Xr fss 4 ,
.Xr fsck 8 ,
.Xr fsck_ffs 8 ,
.Xr mount_msdos 8
.Sh HISTORY
A
.Nm
utility appeared in
.Nx 1.2 .
.Sh BUGS
.Nm
is still under construction.