e2fsck
OPTIONS
-a This option does the same thing as the -p option. It is pro‐
vided for backwards compatibility only; it is suggested that
people use -p option whenever possible.
-b superblock
Instead of using the normal superblock, use an alternative
superblock specified by superblock. This option is normally
used when the primary superblock has been corrupted. The loca‐
tion of the backup superblock is dependent on the filesystem's
blocksize. For filesystems with 1k blocksizes, a backup
superblock can be found at block 8193; for filesystems with 2k
blocksizes, at block 16384; and for 4k blocksizes, at block
32768.
Additional backup superblocks can be determined by using the
mke2fs program using the -n option to print out where the
superblocks were created. The -b option to mke2fs, which spec‐
ifies blocksize of the filesystem must be specified in order for
the superblock locations that are printed out to be accurate.
If an alternative superblock is specified and the filesystem is
not opened read-only, e2fsck will make sure that the primary
superblock is updated appropriately upon completion of the
filesystem check.
-B blocksize
Normally, e2fsck will search for the superblock at various dif‐
ferent block sizes in an attempt to find the appropriate block
size. This search can be fooled in some cases. This option
forces e2fsck to only try locating the superblock at a particu‐
lar blocksize. If the superblock is not found, e2fsck will ter‐
minate with a fatal error.
-c This option causes e2fsck to use badblocks(8) program to do a
read-only scan of the device in order to find any bad blocks.
If any bad blocks are found, they are added to the bad block
inode to prevent them from being allocated to a file or direc‐
tory. If this option is specified twice, then the bad block
scan will be done using a non-destructive read-write test.
-C fd This option causes e2fsck to write completion information to the
specified file descriptor so that the progress of the filesystem
check can be monitored. This option is typically used by pro‐
grams which are running e2fsck. If the file descriptor number
is negative, then absolute value of the file descriptor will be
used, and the progress information will be suppressed initially.
It can later be enabled by sending the e2fsck process a SIGUSR1
signal. If the file descriptor specified is 0, e2fsck will
print a completion bar as it goes about its business. This
requires that e2fsck is running on a video console or terminal.
-d Print debugging output (useless unless you are debugging
e2fsck).
-D Optimize directories in filesystem. This option causes e2fsck
to try to optimize all directories, either by reindexing them if
the filesystem supports directory indexing, or by sorting and
compressing directories for smaller directories, or for filesys‐
tems using traditional linear directories.
Even without the -D option, e2fsck may sometimes optimize a few
directories --- for example, if directory indexing is enabled
and a directory is not indexed and would benefit from being
indexed, or if the index structures are corrupted and need to be
rebuilt. The -D option forces all directories in the filesystem
to be optimized. This can sometimes make them a little smaller
and slightly faster to search, but in practice, you should
rarely need to use this option.
The -D option will detect directory entries with duplicate names
in a single directory, which e2fsck normally does not enforce
for performance reasons.
-E extended_options
Set e2fsck extended options. Extended options are comma sepa‐
rated, and may take an argument using the equals ('=') sign.
The following options are supported:
ea_ver=extended_attribute_version
Set the version of the extended attribute blocks
which e2fsck will require while checking the
filesystem. The version number may be 1 or 2. The
default extended attribute version format is 2.
fragcheck
During pass 1, print a detailed report of any dis‐
contiguous blocks for files in the filesystem.
-f Force checking even if the file system seems clean.
-F Flush the filesystem device's buffer caches before beginning.
Only really useful for doing e2fsck time trials.
-j external-journal
Set the pathname where the external-journal for this filesystem
can be found.
-k When combined with the -c option, any existing bad blocks in the
bad blocks list are preserved, and any new bad blocks found by
running badblocks(8) will be added to the existing bad blocks
list.
-l filename
Add the block numbers listed in the file specified by filename
to the list of bad blocks. The format of this file is the same
as the one generated by the badblocks(8) program. Note that the
block numbers are based on the blocksize of the filesystem.
Hence, badblocks(8) must be given the blocksize of the filesys‐
tem in order to obtain correct results. As a result, it is much
simpler and safer to use the -c option to e2fsck, since it will
assure that the correct parameters are passed to the badblocks
program.
-L filename
Set the bad blocks list to be the list of blocks specified by
filename. (This option is the same as the -l option, except the
bad blocks list is cleared before the blocks listed in the file
are added to the bad blocks list.)
-n Open the filesystem read-only, and assume an answer of `no' to
all questions. Allows e2fsck to be used non-interactively.
This option may not be specified at the same time as the -p or
-y options.
-p Automatically repair ("preen") the file system. This option
will cause e2fsck to automatically fix any filesystem problems
that can be safely fixed without human intervention. If e2fsck
discovers a problem which may require the system administrator
to take additional corrective action, e2fsck will print a
description of the problem and then exit with the value 4 logi‐
cally or'ed into the exit code. (See the EXIT CODE section.)
This option is normally used by the system's boot scripts. It
may not be specified at the same time as the -n or -y options.
-r This option does nothing at all; it is provided only for back‐
wards compatibility.
-t Print timing statistics for e2fsck. If this option is used
twice, additional timing statistics are printed on a pass by
pass basis.
-v Verbose mode.
-V Print version information and exit.
-y Assume an answer of `yes' to all questions; allows e2fsck to be
used non-interactively. This option may not be specified at the
same time as the -n or -p options.
