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SCAN_FFS(8) NetBSD System Manager's Manual SCAN_FFS(8)
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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/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
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 par-
tition if the first superblock has become corrupted. It is
most useful if device refers to the raw device for the par-
tition, 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
NetBSD 9.1 May 1, 2007 NetBSD 9.1