Provided by: e2fsprogs_1.38-2ubuntu2_i386 bug

NAME

       badblocks - search a device for bad blocks

SYNOPSIS

       badblocks  [  -svwnf  ]  [  -b  block-size ] [ -c blocks_at_once ] [ -i
       input_file ] [ -o output_file ] [ -p num_passes ] [ -t  test_pattern  ]
       device [ last-block ] [ start-block ]

DESCRIPTION

       badblocks  is used to search for bad blocks on a device (usually a disk
       partition).  device is the special file  corresponding  to  the  device
       (e.g  /dev/hdc1).  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.
       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.

       Important note: If the output of badblocks is going to be  fed  to  the
       e2fsck  or  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  not  run  badblocks
       directly,  but  rather  use  the  -c  option  of  the e2fsck and mke2fs
       programs.

OPTIONS

       -b block-size
              Specify the size of blocks in bytes.  The default is 1024.

       -c number of blocks
              is the number of blocks which are tested at a time.  The default
              is 64.

       -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
              overridden  using  the  -f flag, but should almost never be used
              --- if you think you’re smarter than the 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.

       -i input_file
              Read  a  list  of  already existing known bad blocks.  Badblocks
              will skip testing these blocks since they are known to  be  bad.
              If  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 new bad blocks produced on the standard output
              or in the output file.  The -b option of 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.

       -o output_file
              Write  the  list  of  bad blocks to the specified file.  Without
              this option, badblocks displays the list on its standard output.
              The  format of this file is suitable for use by the -l option in
              e2fsck(8) or mke2fs(8).

       -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 badblocks will exit after the first pass.

       -t test_pattern
              Specify a test pattern to be read (and written) to disk  blocks.
              The  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 (-w) and non-destructive (-n) modes, one or more test
              patterns  may  be specified by specifying the -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.

       -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 -w option, as they are mutually exclusive.

       -s     Show the progress of the scan by writing out the  block  numbers
              as they are checked.

       -v     Verbose mode.

       -w     Use  write-mode  test. With this option, 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.  This option may not be combined with the  -n  option,
              as they are mutually exclusive.

WARNING

       Never  use  the  -w  option  on  an  device containing an existing file
       system.  This option erases data!  If you want to do write-mode testing
       on  an  existing file system, use the -n option instead.  It is slower,
       but it will preserve your data.

AUTHOR

       badblocks 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>.

AVAILABILITY

       badblocks is part of  the  e2fsprogs  package  and  is  available  from
       http://e2fsprogs.sourceforge.net.

SEE ALSO

       e2fsck(8), mke2fs(8)