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SCAN_FFS(8)                 System Manager's Manual                SCAN_FFS(8)

     scan_ffs, scan_lfs - find FFSv1/FFSv2/LFS partitions on a disk or file

     scan_ffs [-blv] [-e end] [-F file] [-s start] device

     scan_ffs will take a raw disk device that covers the whole disk or a file
     and will find all possible FFSv[12]/LFS partitions, independent of block
     sizes on it.  It will show the file system type (FFSv1, FFSv2, or LFS),
     size, and offset.  Also it has an option to show the values with a
     disklabel-alike output.

     The options are as follows:

     -b           Report every superblock found with its sector address,
                  rather than trying to report the partition boundaries.  This
                  option can be useful to find the other superblocks in a
                  partition if the first superblock has become corrupted.  It
                  is most useful if device refers to the raw device for the
                  partition, rather than the entire disk.

     -e end       Where to stop searching for file systems.  The end argument
                  specifies the last sector that will be searched.  Default is
                  the last sector of device.

     -F file      Path to a file containing possible partitions inside of it.

     -l           Print out a string looking much like the input to disklabel.
                  With a little massaging, this output can usually be used by

     -s start     Where to start searching for file systems.  This makes it
                  easier to skip swap partitions or other large non-UFS/FFS
                  partitions.  The start argument specifies the first sector
                  that will be searched.  Default is the first sector of

     -v           Be verbose about what scan_ffs is doing, and what has been

     The device argument specifies which device scan_ffs should scan for file

     scan_lfs is just another name for the same program, both behave in
     exactly the same way.


     The scan_ffs program first appeared in OpenBSD 2.3 and then in
     NetBSD 3.1.  Support for searching in files was added in NetBSD 4.0.

     scan_ffs was written for OpenBSD by Niklas Hallqvist and Tobias
     Weingartner.  It was ported to NetBSD by Juan Romero Pardines, who added
     support for LFS/FFSv2, partitions with fragsize/blocksize greater than
     2048/16384 for FFSv1, searching on files, etc.

     Currently scan_ffs won't find partitions with fragsize/blocksize greater
     than 8192/65536.

NetBSD 10.99                      May 1, 2007                     NetBSD 10.99