日前启动系统时，报如下错误：
想到文件修复命令fsck，正好不是很熟悉，学学看：
一直很少用man查看命令是如何使用，这是一种不好的习惯，今天就man就着Google共同看下如何使用man及本文的主人公fsck吧，首先man fsck
FSCK(8) FSCK(8)
NAME
fsck - check and repair a Linux file system
SYNOPSIS
fsck [ -sAVRTNP ] [ -C [ fd ] ] [ -t fstype ] [filesys ... ] [--] [ fs-specific-options ]
DESCRIPTION
fsck is used to check and optionally repair one or more Linux file systems. filesys can be a device name (e.g. /dev/hdc1, /dev/sdb2), a mount point (e.g. /, /usr,
/home), or an ext2 label or UUID specifier (e.g. UUID=8868abf6-88c5-4a83-98b8-bfc24057f7bd or LABEL=root). Normally, the fsck program will try to handle filesys-
tems on different physical disk drives in parallel to reduce the total amount of time needed to check all of the filesystems.
If no filesystems are specified on the command line, and the -A option is not specified, fsck will default to checking filesystems in /etc/fstab serially. This is
equivalent to the -As options.
The exit code returned by fsck is the sum of the following conditions:
0 - No errors
1 - File system errors corrected
2 - System should be rebooted
4 - File system errors left uncorrected
8 - Operational error
16 - Usage or syntax error
32 - Fsck canceled by user request
128 - Shared library error
The exit code returned when multiple file systems are checked is the bit-wise OR of the exit codes for each file system that is checked.
In actuality, fsck is simply a front-end for the various file system checkers (fsck.fstype) available under Linux. The file system-specific checker is searched for
in /sbin first, then in /etc/fs and /etc, and finally in the directories listed in the PATH environment variable. Please see the file system-specific checker manual
pages for further details.
OPTIONS
-s Serialize fsck operations. This is a good idea if you are checking multiple filesystems and the checkers are in an interactive mode. (Note: e2fsck(8) runs
in an interactive mode by default. To make e2fsck(8) run in a non-interactive mode, you must either specify the -p or -a option, if you wish for errors to be
corrected automatically, or the -n option if you do not.)
-t fslist
Specifies the type(s) of file system to be checked. When the -A flag is specified, only filesystems that match fslist are checked. The fslist parameter is a
comma-separated list of filesystems and options specifiers. All of the filesystems in this comma-separated list may be prefixed by a negation operator ’no’
or ’!’, which requests that only those filesystems not listed in fslist will be checked. If all of the filesystems in fslist are not prefixed by a negation
operator, then only those filesystems listed in fslist will be checked.
Options specifiers may be included in the comma-separated fslist. They must have the format opts=fs-option. If an options specifier is present, then only
filesystems which contain fs-option in their mount options field of /etc/fstab will be checked. If the options specifier is prefixed by a negation operator,
then only those filesystems that do not have fs-option in their mount options field of /etc/fstab will be checked.
For example, if opts=ro appears in fslist, then only filesystems listed in /etc/fstab with the ro option will be checked.
For compatibility with Mandrake distributions whose boot scripts depend upon an unauthorized UI change to the fsck program, if a filesystem type of loop is
found in fslist, it is treated as if opts=loop were specified as an argument to the -t option.
Normally, the filesystem type is deduced by searching for filesys in the /etc/fstab file and using the corresponding entry. If the type can not be deduced,
and there is only a single filesystem given as an argument to the -t option, fsck will use the specified filesystem type. If this type is not available, then
the default file system type (currently ext2) is used.
-A Walk through the /etc/fstab file and try to check all file systems in one run. This option is typically used from the /etc/rc system initialization file,
instead of multiple commands for checking a single file system.
The root filesystem will be checked first unless the -P option is specified (see below). After that, filesystems will be checked in the order specified by
the fs_passno (the sixth) field in the /etc/fstab file. Filesystems with a fs_passno value of 0 are skipped and are not checked at all. Filesystems with a
fs_passno value of greater than zero will be checked in order, with filesystems with the lowest fs_passno number being checked first. If there are multiple
filesystems with the same pass number, fsck will attempt to check them in parallel, although it will avoid running multiple filesystem checks on the same
physical disk.
Hence, a very common configuration in /etc/fstab files is to set the root filesystem to have a fs_passno value of 1 and to set all other filesystems to have a
fs_passno value of 2. This will allow fsck to automatically run filesystem checkers in parallel if it is advantageous to do so. System administrators might
choose not to use this configuration if they need to avoid multiple filesystem checks running in parallel for some reason --- for example, if the machine in
question is short on memory so that excessive paging is a concern.
-C [ fd ]
Display completion/progress bars for those filesystem checkers (currently only for ext2 and ext3) which support them. Fsck will manage the filesystem check-
ers so that only one of them will display a progress bar at a time. GUI front-ends may specify a file descriptor fd, in which case the progress bar informa-
tion will be sent to that file descriptor.
-N Don’t execute, just show what would be done.
-P When the -A flag is set, check the root filesystem in parallel with the other filesystems. This is not the safest thing in the world to do, since if the root
filesystem is in doubt things like the e2fsck(8) executable might be corrupted! This option is mainly provided for those sysadmins who don’t want to reparti-
tion the root filesystem to be small and compact (which is really the right solution).
-R When checking all file systems with the -A flag, skip the root file system (in case it’s already mounted read-write).
-T Don’t show the title on startup.
-V Produce verbose output, including all file system-specific commands that are executed.
fs-specific-options
Options which are not understood by fsck are passed to the filesystem-specific checker. These arguments must not take arguments, as there is no way for fsck
to be able to properly guess which arguments take options and which don’t.
Options and arguments which follow the -- are treated as file system-specific options to be passed to the file system-specific checker.
Please note that fsck is not designed to pass arbitrarily complicated options to filesystem-specific checkers. If you’re doing something complicated, please
just execute the filesystem-specific checker directly. If you pass fsck some horribly complicated option and arguments, and it doesn’t do what you expect,
don’t bother reporting it as a bug. You’re almost certainly doing something that you shouldn’t be doing with fsck.
Options to different filesystem-specific fsck’s are not standardized. If in doubt, please consult the man pages of the filesystem-specific checker. Although not
guaranteed, the following options are supported by most file system checkers:
-a Automatically repair the file system without any questions (use this option with caution). Note that e2fsck(8) supports -a for backwards compatibility only.
This option is mapped to e2fsck’s -p option which is safe to use, unlike the -a option that some file system checkers support.
-n For some filesystem-specific checkers, the -n option will cause the fs-specific fsck to avoid attempting to repair any problems, but simply report such prob-
lems to stdout. This is however not true for all filesystem-specific checkers. In particular, fsck.reiserfs(8) will not report any corruption if given this
option. fsck.minix(8) does not support the -n option at all.
-r Interactively repair the filesystem (ask for confirmations). Note: It is generally a bad idea to use this option if multiple fsck’s are being run in paral-
lel. Also note that this is e2fsck’s default behavior; it supports this option for backwards compatibility reasons only.
-y For some filesystem-specific checkers, the -y option will cause the fs-specific fsck to always attempt to fix any detected filesystem corruption automati-
cally. Sometimes an expert may be able to do better driving the fsck manually. Note that not all filesystem-specific checkers implement this option. In
particular fsck.minix(8) and fsck.cramfs(8) does not support the -y option as of this writing.
AUTHOR
Theodore Ts’o ([email protected])
FILES
/etc/fstab.
ENVIRONMENT VARIABLES
The fsck program’s behavior is affected by the following environment variables:
FSCK_FORCE_ALL_PARALLEL
If this environment variable is set, fsck will attempt to run all of the specified filesystems in parallel, regardless of whether the filesystems appear to be
on the same device. (This is useful for RAID systems or high-end storage systems such as those sold by companies such as IBM or EMC.)
FSCK_MAX_INST
This environment variable will limit the maximum number of file system checkers that can be running at one time. This allows configurations which have a
large number of disks to avoid fsck starting too many file system checkers at once, which might overload CPU and memory resources available on the system. If
this value is zero, then an unlimited number of processes can be spawned. This is currently the default, but future versions of fsck may attempt to automati-
cally determine how many file system checks can be run based on gathering accounting data from the operating system.
PATH The PATH environment variable is used to find file system checkers. A set of system directories are searched first: /sbin, /sbin/fs.d, /sbin/fs, /etc/fs, and
/etc. Then the set of directories found in the PATH environment are searched.
FSTAB_FILE
This environment variable allows the system administrator to override the standard location of the /etc/fstab file. It is also useful for developers who are
testing fsck.
SEE ALSO
fstab(5), mkfs(8), fsck.ext2(8) or fsck.ext3(8) or e2fsck(8), cramfsck(8), fsck.minix(8), fsck.msdos(8), fsck.jfs(8), fsck.nfs(8), fsck.vfat(8), fsck.xfs(8),
fsck.xiafs(8), reiserfsck(8).
E2fsprogs version 1.39 May 2006 FSCK(8)
(END)
一大堆，先暂时不管，fsck --help看下：
[root@uyhd000225 ~]# fsck --help
fsck 1.39 (29-May-2006)
fsck.ext3: invalid option -- h
Usage: fsck.ext3 [-panyrcdfvstDFSV] [-b superblock] [-B blocksize]
[-I inode_buffer_blocks] [-P process_inode_size]
[-l|-L bad_blocks_file] [-C fd] [-j external_journal]
[-E extended-options] device
Emergency help:
-p Automatic repair (no questions)
-n Make no changes to the filesystem
-y Assume "yes" to all questions
-c Check for bad blocks and add them to the badblock list
-f Force checking even if filesystem is marked clean
-v Be verbose
-b superblock Use alternative superblock
-B blocksize Force blocksize when looking for superblock
-j external_journal Set location of the external journal
-l bad_blocks_file Add to badblocks list
-L bad_blocks_file Set badblocks list
可以看出下面是上面的精简版。
linux中文介绍Google搜索
Linux命令：fsck
功能说明： 检查文件系统并尝试修复错误。
语 法：
fsck [-aANPrRsTV][-t <文件系统类型>][文件系统...]补充说明：
当文件系统发生错误四化，可用fsck指令尝试加以修复。参 数：
-a 自动修复文件系统，不询问任何问题。
-A 依照/etc/fstab配置文件的内容，检查文件内所列的全部文件系统。
-N 不执行指令，仅列出实际执行会进行的动作。
-P 当搭配"-A"参数使用时，则会同时检查所有的文件系统。
-r 采用互动模式，在执行修复时询问问题，让用户得以确认并决定处理方式。
-R 当搭配"-A"参数使用时，则会略过/目录的文件系统不予检查。
-s 依序执行检查作业，而非同时执行。
-t<文件系统类型> 指定要检查的文件系统类型。
-T 执行fsck指令时，不显示标题信息。
-V 显示指令执行过程。用fsck检查文件系统完整性
文件系统很复杂，因此易于发生错误。可以用fsck 命令检查文件系统是否正确和有效。它可以根据指令修复找到的小错误，并将未修复错误报告用户。幸运的是，文件系统的代码非常有效，所以根本极少出现问题，并且问题通常原因是电源失败、硬件失败、或操作错误，例如没有正常关闭系统。
大多数系统设置为启动时自动运行fsck ，因此任何错误将在系统使用前被检测到(并根据希望修正)。使用有错误的文件系统可能使问题变得更坏：如果数据结构有问题，使用这个文件系统可能使之更糟，导致更多的数据丢失。当然，在大的文件系统上运行fsck 会花一定的时间，如果系统正常关闭，几乎从不发生错误，因此有一些方法可以不进行检查。如果文件/etc/fastboot 存在，就不检查。
另外，如果ext2文件系统在超级快中有一个特定的标记告知该文件系统在上次mount后没有正常unmount. 如果标记指出unmount正常完成(假设正常unmount指出没问题)，e2fsck (fsck 的ext2文件系统版) 就不检查系统。/etc/fastboot 是否影响系统依赖于你的启动手稿，但ext2标记则在你使用e2fsck 时发生作用--基于一个e2fsck 选项(参阅e2fsck 手册页)
自动检查只对启动时自动mount的文件系统发生作用。使用fsck 手工检查其他文件系统，比如软盘。
如果fsck 发现为修复的问题，你需要深入了解文件系统的一般工作原理和有问题的文件系统的细节，或好的备份。最后一个办法容易(虽然冗长)安排，如果你自己不知道，有时可以通过朋友、linux新闻组、电子邮件列表或其他支持源安排。我很想告诉你更多，但我对这的学习和实践也并不多。theodore t'so的debugfs 程序应该有用。
fsck 只能运行于未mount的文件系统，不要用于已mount的文件系统(除了启动时的只读根文件系统)。这是因为它存取原始磁盘，在操作系统不知道的情况下修改文件系统。 there will be trouble, if the operating system is confused.