xref: /freebsd/sbin/fsck/fsck.8 (revision bb15ca603fa442c72dde3f3cb8b46db6970e3950)
1.\"	$NetBSD: fsck.8,v 1.19 1999/03/10 00:08:33 erh Exp $
2.\"
3.\" Copyright (c) 1996 Christos Zoulas.  All rights reserved.
4.\"
5.\" Redistribution and use in source and binary forms, with or without
6.\" modification, are permitted provided that the following conditions
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13.\" 3. All advertising materials mentioning features or use of this software
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15.\"	This product includes software developed by Christos Zoulas.
16.\" 4. The name of the author may not be used to endorse or promote products
17.\"    derived from this software without specific prior written permission.
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30.\" $FreeBSD$
31.\"
32.Dd January 25, 2009
33.Dt FSCK 8
34.Os
35.Sh NAME
36.Nm fsck
37.Nd file system consistency check and interactive repair
38.Sh SYNOPSIS
39.Nm
40.Op Fl Cdfnpvy
41.Op Fl B | F
42.Op Fl T Ar fstype : Ns Ar fsoptions
43.Op Fl t Ar fstype
44.Op Fl c Ar fstab
45.Oo Ar special | node Oc ...
46.Sh DESCRIPTION
47The
48.Nm
49utility invokes file system-specific programs to check
50the special devices listed in the
51.Xr fstab 5
52file or in the command line for consistency.
53.Pp
54It is normally used in the script
55.Pa /etc/rc
56during automatic reboot.
57Traditionally,
58.Nm
59is invoked before the file systems are mounted
60and all checks are done to completion at that time.
61If background checking is available,
62.Nm
63is invoked twice.
64It is first invoked at the traditional time,
65before the file systems are mounted, with the
66.Fl F
67flag to do checking on all the file systems
68that cannot do background checking.
69It is then invoked a second time,
70after the system has completed going multiuser, with the
71.Fl B
72flag to do checking on all the file systems
73that can do background checking.
74Unlike the foreground checking,
75the background checking is started asynchronously
76so that other system activity can proceed
77even on the file systems that are being checked.
78.Pp
79If no file systems are specified,
80.Nm
81reads the table
82.Pa /etc/fstab
83to determine which file systems to check.
84Only partitions in
85.Pa /etc/fstab
86that are mounted
87.Dq rw ,
88.Dq rq
89or
90.Dq ro
91and that have non-zero pass number are checked.
92File systems with pass number 1 (normally just the root file system)
93are always checked one at a time.
94.Pp
95If not in preen mode, the remaining entries are checked in order of
96increasing pass number one at a time.
97This is needed when interaction with
98.Nm
99is required.
100.Pp
101In preen mode, after pass 1 completes, all remaining file systems are checked,
102in pass number order running one process per disk drive in parallel for each
103pass number in increasing order.
104.Pp
105In other words: In preen mode all pass 1 partitions are checked sequentially.
106Next all pass 2 partitions are checked in parallel, one process per disk drive.
107Next all pass 3 partitions are checked in parallel, one process per disk drive.
108etc.
109.Pp
110The disk drive containing each file system is inferred from the shortest prefix
111of the device name that ends in a digit; the remaining characters are assumed
112to be the partition and slice designators.
113.Pp
114The options are as follows:
115.Bl -tag -width indent
116.It Fl C
117Check if the
118.Dq clean
119flag is set in the superblock and skip file system checks if file system was
120properly dismounted and marked clean.
121.It Fl c Ar fstab
122Specify the
123.Pa fstab
124file to use.
125.It Fl d
126Debugging mode.
127Just print the commands without executing them.
128Available
129only if
130.Nm
131is compiled to support it.
132.It Fl f
133Force checking of file systems, even when they are marked clean (for file systems
134that support this).
135.It Fl n
136Causes
137.Nm
138to assume no as the answer to all operator questions, except "CONTINUE?".
139.It Fl p
140Enter preen mode.
141In preen mode, only a restricted class of innocuous
142file system inconsistencies will be corrected.
143If unexpected inconsistencies caused by hardware or
144software failures are encountered, the check program
145will exit with a failure.
146See the manual pages for the individual check programs
147for a list of the sorts of failures that they correct
148when running in preen mode.
149.It Fl F
150Run in foreground mode.
151The check program for each file system is invoked with the
152.Fl F
153flag to determine whether it wishes to run as part of
154the boot up sequence,
155or if it is able to do its job in background after the
156system is up and running.
157A non-zero exit code indicates that it wants to run in foreground
158and the check program is invoked.
159A zero exit code indicates that it is able to run later in background
160and just a deferred message is printed.
161.It Fl B
162Run in background mode.
163The check program for each file system is invoked with the
164.Fl F
165flag to determine whether it wishes to run as part of
166the boot up sequence,
167or if it is able to do its job in background after the
168system is up and running.
169A non-zero exit code indicates that it wanted to run in foreground
170which is assumed to have been done, so the file system is skipped.
171A zero exit code indicates that it is able to run in background
172so the check program is invoked with the
173.Fl B
174flag to indicate that a check on the active file system should be done.
175When running in background mode,
176only one file system at a time will be checked.
177Note that background
178.Nm
179is limited to checking for only the most commonly occurring
180file system abnormalities.
181Under certain circumstances,
182some errors can escape background
183.Nm .
184It is recommended that you perform foreground
185.Nm
186on your systems periodically and whenever you encounter
187file-system\-related panics.
188.It Fl t Ar fstype
189Invoke
190.Nm
191only for the comma separated list of file system types.
192If the
193list starts with
194.Dq no
195then invoke
196.Nm
197for the file system types that are not specified in the list.
198.It Fl v
199Print the commands before executing them.
200.It Fl y
201Causes
202.Nm
203to assume yes
204as the answer to all operator questions.
205.It Fl T Ar fstype : Ns Ar fsoptions
206List of comma separated file system specific options for the specified
207file system type, in the same format as
208.Xr mount 8 .
209.El
210.Sh FILES
211.Bl -tag -width /etc/fstab -compact
212.It Pa /etc/fstab
213file system table
214.El
215.Sh SEE ALSO
216.Xr fstab 5 ,
217.Xr fsck_ffs 8 ,
218.Xr fsck_msdosfs 8 ,
219.Xr mount 8
220