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1 perry 1 FSCK
2 !!!FSCK
3 NAME
4 SYNOPSIS
5 DESCRIPTION
6 OPTIONS
7 AUTHOR
8 FILES
9 ENVIRONMENT VARIABLES
10 SEE ALSO
11 ----
12 !!NAME
13
14
15 fsck - check and repair a Linux file system
16 !!SYNOPSIS
17
18
19 __fsck__ [[ __-sACVRTNP__ ] [[ __-t__ ''fstype'' ]
20 ''filesys [[ ... ]'' [[--] [[ __fsck-options__
21 ]
22 !!DESCRIPTION
23
24
25 __fsck__ is used to check and optionally repair a one or
26 more Linux file systems. ''filesys'' can be a device name
27 (e.g. ''/dev/hdc1'', ''/dev/sdb2''), a mount point
28 (e.g. ''/'', ''/usr'', ''/home''), or an ext2 label
29 or UUID specifier (e.g.
30 UUID=8868abf6-88c5-4a83-98b8-bfc24057f7bd or LABEL=root).
31 The __fsck__ program will try to run filesystems on
32 different physical disk drives in parallel to reduce total
33 amount time to check all of the filesystems.
34
35
36 The exit code returned by __fsck__ is the sum of the
37 following conditions:
38 0 - No errors
39 1 - File system errors corrected
40 2 - System should be rebooted
41 4 - File system errors left uncorrected
42 8 - Operational error
43 16 - Usage or syntax error
44 128 - Shared library error
45 The exit code returned when all file systems are checked
46 using the __-A__ option is the bit-wise OR of the exit
47 codes for each file system that is checked.
48
49
50 In actuality, __fsck__ is simply a front-end for the
51 various file system checkers (__fsck__.''fstype'')
52 available under Linux. The file system-specific checker is
53 searched for in ''/sbin'' first, then in ''/etc/fs''
54 and ''/etc'', and finally in the directories listed in
55 the PATH environment variable. Please see the file
56 system-specific checker manual pages for further
57 details.
58 !!OPTIONS
59
60
61 __-s__
62
63
64 Serialize __fsck__ operations. This is a good idea if you
65 checking multiple filesystems and the checkers are in an
2 perry 66 interactive mode. (Note: e2fsck(8) runs in an
67 interactive mode by default. To make e2fsck(8) run in
1 perry 68 a non-interactive mode, you must either specify the
69 __-p__ or __-a__ option, if you wish for errors to be
70 corrected automatically, or the __-n__ option if you do
71 not.)
72
73
74 __-t__ ''fslist''
75
76
77 Specifies the type(s) of file system to be checked. When the
78 __-A__ flag is specified, only filesystems that match
79 ''fslist'' are checked. The ''fslist'' parameter is a
80 comma-separated list of filesystems and options specifiers.
81 All of the filesystems in this comma-separated list may be
82 prefixed by a negation operator '__no__' or '__!__',
83 which requests that only those filesystems not listed in
84 ''fslist'' will be checked. If all of the filesystems in
85 ''fslist'' are not prefixed by a negation operator, then
86 only those filesystems listed in ''fslist'' will be
87 checked.
88
89
90 Options specifiers may be included in the comma separated
91 ''fslist''. They must have the format
92 __opts=__''fs-option'', and may be prefixed by a
93 negation operator. If an options specifier is present, then
94 only filesystems whose __/etc/fstab__ entry do (or do
95 not, if the options specifier was prefixed by a negation
96 operator) contain ''fs-option'' in their options field of
97 the __/etc/fstab__ file will be checked.
98
99
100 For compatibility with Mandrake distributions whose boot
101 scripts depend upon an unauthorized UI change to the
102 __fsck__ program, if a filesystem type of __loop__ is
103 found in ''fslist'', it is treated as if __opts=loop__
104 were specified as an argument to the __-t__
105 option.
106
107
108 Normally, the filesystem type is deduced by searching for
109 ''filesys'' in the ''/etc/fstab'' file and using the
110 corresponding entry. If the type can not be deduced, and
111 there is only a single filesystem given as an argument to
112 the __-t__ option, __fsck__ will use the specified
113 filesystem type. If this type is not available, then the
114 default file system type (currently ext2) is
115 used.
116
117
118 __-A__
119
120
121 Walk through the ''/etc/fstab'' file and try to check all
122 file systems in one run. This option is typically used from
123 the ''/etc/rc'' system initalization file, instead of
124 multiple commands for checking a single file
125 system.
126
127
128 The root filesystem will be checked first unless the
129 __-P__ option is specified (see below). After that,
130 filesystems will be checked in the order specified by the
131 ''fs_passno'' (the sixth) field in the ''/etc/fstab''
132 file. Filesystems with a ''fs_passno'' value of 0 are
133 skipped and are not checked at all. Filesystems with a
134 ''fs_passno'' value of greater than zero will be checked
135 in order, with filesystems with filesystems with the lowest
136 ''fs_passno'' number being checked first. If there are
137 multiple filesystems with the same pass number, fsck will
138 attempt to check them in parallel, although it will avoid
139 running multiple filesystem checks on the same physical
140 disk.
141
142
143 Hence, a very common configuration in ''/etc/fstab''
144 files is to set the root filesystem to have a
145 ''fs_passno'' value of 1 and to set all filesystems to
146 have a ''fs_passno'' value of 2. This will allow
147 __fsck__ to automatically run filesystem checkers in
148 parallel if it is advantageous to do so. System
149 administrators might choose not to use this configuration if
150 they need to avoid multiple filesystem checks running in
151 parallel for some reason --- for example, if the machine in
152 question is short on memory so that excessive paging is a
153 concern.
154
155
156 __-C__
157
158
159 Display completion/progress bars for those filesystems
160 checkers (currently only for ext2) which support them. Fsck
161 will manage the filesystem checkers so that only one of them
162 will display a progress bar at a time.
163
164
165 __-N__
166
167
168 Don't execute, just show what would be done.
169
170
171 __-P__
172
173
174 When the __-A__ flag is set, check the root filesystem in
175 parallel with the other filesystems. This is not the safest
176 thing in the world to do, since if the root filesystem is in
2 perry 177 doubt things like the e2fsck(8) executable might be
1 perry 178 corrupted! This option is mainly provided for those
179 sysadmins who don't want to repartition the root filesystem
180 to be small and compact (which is really the right
181 solution).
182
183
184 __-R__
185
186
187 When checking all file systems with the __-A__ flag, skip
188 the root file system (in case it's already mounted
189 read-write).
190
191
192 __-T__
193
194
195 Don't show the title on startup.
196
197
198 __-V__
199
200
201 Produce verbose output, including all file system-specific
202 commands that are executed.
203
204
205 __fsck-options__
206
207
208 Options which which are not understood by __fsck__ are
209 passed to the filesystem-specific checker. These arguments
210 __must__ not take arguments, as there is no way for
211 __fsck__ to be able to properly guess which arguments
212 take options and which don't.
213
214
215 Options and arguments which follow the __--__ are treated
216 as file system-specific options to be passed to the file
217 system-specific checker.
218
219
220 Please note that fsck is not designed to pass arbitrarily
221 complicated options to filesystem-specific checkers. If
222 you're doing something complicated, please just execute the
223 filesystem-specific checker directly. If you pass
224 __fsck__ some horribly complicated option and arguments,
225 and it doesn't do what you expect, __don't bother reporting
226 it as a bug.__ You're almost certainly doing something
227 that you shouldn't be doing with __fsck.__
228
229
230 Currently, standardized file system-specific options are
231 somewhat in flux. Although not guaranteed, the following
232 options are supported by most file system
233 checkers:
234
235
236 __-a__
237
238
239 Automatically repair the file system without any questions
2 perry 240 (use this option with caution). Note that e2fsck(8)
1 perry 241 supports __-a__ for backwards compatibility only. This
242 option is mapped to __e2fsck__'s __-p__ option which
243 is safe to use, unlike the __-a__ option that most file
244 system checkers support.
245
246
247 __-r__
248
249
250 Interactively repair the filesystem (ask for confirmations).
251 Note: It is generally a bad idea to use this option if
252 multiple fsck's are being run in parallel. Also note that
253 this is __e2fsck__'s default behavior; it supports this
254 option for backwards compatibility reasons
255 only.
256 !!AUTHOR
257
258
259 Theodore Ts'o (tytso@mit.edu)
260 !!FILES
261
262
263 ''/etc/fstab''.
264 !!ENVIRONMENT VARIABLES
265
266
267 The __fsck__ program's behavior is affected by the
268 following environment variables:
269
270
271 __FSCK_FORCE_ALL_PARALLEL__
272
273
274 If this environment variable is set, __fsck__ will
275 attempt to run all of the specified filesystems in parallel,
276 regardless of whether the filesystems appear to be on the
277 same device. (This is useful for RAID systems or high-end
278 storage systems such as those sold by companies such as IBM
279 or EMC.)
280
281
282 __FSCK_MAX_INST__
283
284
285 This environment variable will limit the maximum number of
286 file system checkers that can be running at one time. This
287 allows configurations which have a large number of disks to
288 avoid __fsck__ starting too many file system checkers at
289 once, which might overload CPU and memory resources
290 available on the system. If this value is zero, then an
291 unlimited number of processes can be spawned. This is
292 currently the default, but future versions of __fsck__
293 may attempt to automatically determine how many file system
294 checks can be run based on gathering accounting data from
295 the operating system.
296
297
298 __PATH__
299
300
301 The __PATH__ environment variable is used to find file
302 system checkers. A set of system directories are searched
303 first: __/sbin__, __/sbin/fs.d__, __/sbin/fs__,
304 __/etc/fs__, and __/etc__. Then the set of directories
305 found in the __PATH__ environment are
306 searched.
307
308
309 __FSTAB_FILE__
310
311
312 This environment variable allows the system administrator to
313 override the standard location of the __/etc/fstab__
314 file. It is also use for developers who are testing
315 __fsck__.
316 !!SEE ALSO
317
318
2 perry 319 fstab(5), mkfs(8), fsck.minix(8),
320 fsck.ext2(8) or __e2fsck__(8),
321 fsck.xiafs(8).
1 perry 322 ----
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