.SH SYNOPSIS
.B badblocks
[
+.B \-svwnf
+]
+[
.B \-b
.I block-size
]
[
+.B \-c
+.I blocks_at_once
+]
+[
+.B \-i
+.I input_file
+]
+[
.B \-o
.I output_file
]
[
-.B \-s
+.B \-p
+.I num_passes
]
[
-.B \-v
+.B \-t
+.I test_pattern
]
+.I device
[
-.B \-w
+.I last-block
+] [
+.I start-block
]
-.I device
-.IR blocks-count [ start-block ]
.SH DESCRIPTION
.B badblocks
is used to search for bad blocks on a device (usually a disk partition).
.I device
is the special file corresponding to the device (e.g
.IR /dev/hdc1 ).
-.I blocks-count
-is the number of blocks on the device.
+.I last-block
+is the last block to be checked; if it is not specified, the last block
+on the device is used as a default.
+.I start-block
+is an optional parameter specifying the starting block number
+for the test, which allows the testing to start in the middle of the
+disk. If it is not specified the first block on the disk is used as a default.
+.PP
+.B Important note:
+If the output of
+.B badblocks
+is going to be fed to the
+.B e2fsck
+or
+.B mke2fs
+programs, it is important that the block size is properly specified,
+since the block numbers which are generated are very dependent on the
+block size in use by the filesystem.
+For this reason, it is strongly recommended that
+users
+.B not
+run
+.B badblocks
+directly, but rather use the
+.B \-c
+option of the
+.B e2fsck
+and
+.B mke2fs
+programs.
.SH OPTIONS
.TP
.BI \-b " block-size"
-Specify the size of blocks in bytes.
+Specify the size of blocks in bytes. The default is 1024.
+.TP
+.BI \-c " number of blocks"
+is the number of blocks which are tested at a time. The default is 64.
+.TP
+.B \-f
+Normally, badblocks will refuse to do a read/write or a non-destructive
+test on a device which is mounted, since either can cause the system to
+potentially crash and/or damage the filesystem even if it is mounted
+read-only. This can be overriden using the
+.B \-f
+flag, but should almost never be used --- if you think you're smarter
+than the
+.B badblocks
+program, you almost certainly aren't. The only time when this option
+might be safe to use is if the /etc/mtab file is incorrect, and the device
+really isn't mounted.
+.TP
+.BI \-i " input_file"
+Read a list of already existing known bad blocks.
+.B Badblocks
+will skip testing these blocks since they are known to be bad. If
+.I input_file
+is specified as "-", the list will be read from the standard input.
+Blocks listed in this list will be omitted from the list of
+.I new
+bad blocks produced on the standard output or in the output file.
+The
+.B \-b
+option of
+.BR dumpe2fs (8)
+can be used to retrieve the list of blocks currently marked bad on
+an existing filesystem, in a format suitable for use with this option.
.TP
.BI \-o " output_file"
-Write the list of bad blocks to the specified file. Without this option,
+Write the list of bad blocks to the specified file. Without this option,
.B badblocks
displays the list on its standard output. The format of this file is suitable
for use by the
+.
.B \-l
option in
.BR e2fsck (8)
or
.BR mke2fs (8).
.TP
+.BI \-p " num_passes"
+Repeat scanning the disk until there are no new blocks discovered in
+num_passes consecutive scans of the disk.
+Default is 0, meaning
+.B badblocks
+will exit after the first pass.
+.TP
+.BI \-t " test_pattern"
+Specify a test pattern to be read (and written) to disk blocks. The
+.I test_pattern
+may either be a numeric value between 0 and ULONG_MAX-1 inclusive, or the word
+"random", which specifies that the block should be filled with a random
+bit pattern.
+For read/write (\fB-w\fR) and non-destructive (\fB-n\fR) modes,
+one or more test patterns may be specified by specifiying the
+.B -t
+option for each test pattern desired. For
+read-only mode only a single pattern may be specified and it may not be
+"random". Read-only testing with a pattern assumes that the
+specified pattern has previously been written to the disk - if not, large
+numbers of blocks will fail verification.
+If multiple patterns
+are specified then all blocks will be tested with an one pattern
+before proceeding to the next pattern.
+.TP
+.B \-n
+Use non-destructive read-write mode. By default only a non-destructive
+read-only test is done. This option must not be combined with the
+.B \-w
+option, as they are mutually exclusive.
+.TP
.B \-s
Show the progress of the scan by writing out the block numbers as they
are checked.
Use write-mode test. With this option,
.B badblocks
scans for bad blocks by writing some patterns (0xaa, 0x55, 0xff, 0x00) on
-every block of the device, reading every block and comparing the contents.
+every block of the device, reading every block and comparing the contents.
+This option may not be combined with the
+.B \-n
+option, as they are mutually exclusive.
.SH WARNING
Never use the
.B \-w
option on an device containing an existing file system.
-This option erases data!
+This option erases data! If you want to do write-mode testing on
+an existing file system, use the
+.B \-n
+option instead. It is slower, but it will preserve your data.
.SH AUTHOR
.B badblocks
-was written by Remy Card <card@masi.ibp.fr>, the developer and maintainer
-of the ext2 fs.
-.SH BUGS
-I had no chance to make real tests of this program since I use IDE drives,
-which remap bad blocks. I only made some tests on floppies.
+was written by Remy Card <Remy.Card@linux.org>. Current maintainer is
+Theodore Ts'o <tytso@alum.mit.edu>. Non-destructive read/write test
+implemented by David Beattie <dbeattie@softhome.net>.
.SH AVAILABILITY
.B badblocks
-is part of the e2fsprogs package and is available for anonymous
-ftp from tsx-11.mit.edu in /pub/linux/packages/ext2fs.
+is part of the e2fsprogs package and is available from
+http://e2fsprogs.sourceforge.net.
.SH SEE ALSO
.BR e2fsck (8),
.BR mke2fs (8)
git://git.whamcloud.com / tools / e2fsprogs.git / blobdiff