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 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright 9.\" notice, this list of conditions and the following disclaimer. 10.\" 2. Redistributions in binary form must reproduce the above copyright 11.\" notice, this list of conditions and the following disclaimer in the 12.\" documentation and/or other materials provided with the distribution. 13.\" 3. All advertising materials mentioning features or use of this software 14.\" must display the following acknowledgement: 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. 18.\" 19.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 20.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 21.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 22.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 23.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 24.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 28.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29.\" 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.Oo Ar special | node Oc ... 45.Sh DESCRIPTION 46The 47.Nm 48utility invokes file system-specific programs to check 49the special devices listed in the 50.Xr fstab 5 51file or in the command line for consistency. 52.Pp 53It is normally used in the script 54.Pa /etc/rc 55during automatic reboot. 56Traditionally, 57.Nm 58is invoked before the file systems are mounted 59and all checks are done to completion at that time. 60If background checking is available, 61.Nm 62is invoked twice. 63It is first invoked at the traditional time, 64before the file systems are mounted, with the 65.Fl F 66flag to do checking on all the file systems 67that cannot do background checking. 68It is then invoked a second time, 69after the system has completed going multiuser, with the 70.Fl B 71flag to do checking on all the file systems 72that can do background checking. 73Unlike the foreground checking, 74the background checking is started asynchronously 75so that other system activity can proceed 76even on the file systems that are being checked. 77.Pp 78If no file systems are specified, 79.Nm 80reads the table 81.Pa /etc/fstab 82to determine which file systems to check. 83Only partitions in 84.Pa /etc/fstab 85that are mounted 86.Dq rw , 87.Dq rq 88or 89.Dq ro 90and that have non-zero pass number are checked. 91File systems with pass number 1 (normally just the root file system) 92are always checked one at a time. 93.Pp 94If not in preen mode, the remaining entries are checked in order of 95increasing pass number one at a time. 96This is needed when interaction with 97.Nm 98is required. 99.Pp 100In preen mode, after pass 1 completes, all remaining file systems are checked, 101in pass number order running one process per disk drive in parallel for each 102pass number in increasing order. 103.Pp 104In other words: In preen mode all pass 1 partitions are checked sequentially. 105Next all pass 2 partitions are checked in parallel, one process per disk drive. 106Next all pass 3 partitions are checked in parallel, one process per disk drive. 107etc. 108.Pp 109The disk drive containing each file system is inferred from the shortest prefix 110of the device name that ends in a digit; the remaining characters are assumed 111to be the partition and slice designators. 112.Pp 113The options are as follows: 114.Bl -tag -width indent 115.It Fl C 116Check if the 117.Dq clean 118flag is set in the superblock and skip file system checks if file system was 119properly dismounted and marked clean. 120.It Fl d 121Debugging mode. 122Just print the commands without executing them. 123Available 124only if 125.Nm 126is compiled to support it. 127.It Fl f 128Force checking of file systems, even when they are marked clean (for file systems 129that support this). 130.It Fl n 131Causes 132.Nm 133to assume no as the answer to all operator questions, except "CONTINUE?". 134.It Fl p 135Enter preen mode. 136In preen mode, only a restricted class of innocuous 137file system inconsistencies will be corrected. 138If unexpected inconsistencies caused by hardware or 139software failures are encountered, the check program 140will exit with a failure. 141See the manual pages for the individual check programs 142for a list of the sorts of failures that they correct 143when running in preen mode. 144.It Fl F 145Run in foreground mode. 146The check program for each file system is invoked with the 147.Fl F 148flag to determine whether it wishes to run as part of 149the boot up sequence, 150or if it is able to do its job in background after the 151system is up and running. 152A non-zero exit code indicates that it wants to run in foreground 153and the check program is invoked. 154A zero exit code indicates that it is able to run later in background 155and just a deferred message is printed. 156.It Fl B 157Run in background mode. 158The check program for each file system is invoked with the 159.Fl F 160flag to determine whether it wishes to run as part of 161the boot up sequence, 162or if it is able to do its job in background after the 163system is up and running. 164A non-zero exit code indicates that it wanted to run in foreground 165which is assumed to have been done, so the file system is skipped. 166A zero exit code indicates that it is able to run in background 167so the check program is invoked with the 168.Fl B 169flag to indicate that a check on the active file system should be done. 170When running in background mode, 171only one file system at a time will be checked. 172Note that background 173.Nm 174is limited to checking for only the most commonly occurring 175file system abnormalities. 176Under certain circumstances, 177some errors can escape background 178.Nm . 179It is recommended that you perform foreground 180.Nm 181on your systems periodically and whenever you encounter 182file-system\-related panics. 183.It Fl t Ar fstype 184Invoke 185.Nm 186only for the comma separated list of file system types. 187If the 188list starts with 189.Dq no 190then invoke 191.Nm 192for the file system types that are not specified in the list. 193.It Fl v 194Print the commands before executing them. 195.It Fl y 196Causes 197.Nm 198to assume yes 199as the answer to all operator questions. 200.It Fl T Ar fstype : Ns Ar fsoptions 201List of comma separated file system specific options for the specified 202file system type, in the same format as 203.Xr mount 8 . 204.El 205.Sh FILES 206.Bl -tag -width /etc/fstab -compact 207.It Pa /etc/fstab 208file system table 209.El 210.Sh SEE ALSO 211.Xr fstab 5 , 212.Xr fsck_ffs 8 , 213.Xr fsck_msdosfs 8 , 214.Xr mount 8 215