NAME
fsdb - FFS debugging/editing tool
SYNOPSIS
fsdb [-d] [-f] [-r] fsname
DESCRIPTION
The fsdb utility opens fsname (usually a raw disk partition) and runs a
command loop allowing manipulation of the file system’s inode data. You
are prompted to enter a command with fsdb (inum X)> where X is the
currently selected i-number. The initial selected inode is the root of
the file system (i-number 2). The command processor uses the editline(3)
library, so you can use command line editing to reduce typing if desired.
When you exit the command loop, the file system superblock is marked
dirty and any buffered blocks are written to the file system.
The following options are available:
-d Enable additional debugging output (which comes primarily from
fsck(8)-derived code).
-f Left for historical reasons and has no meaning.
-r Open the file system read/only, and disables all commands that
would write to it.
COMMANDS
Besides the built-in editline(3) commands, fsdb supports these commands:
help Print out the list of accepted commands.
inode i-number
Select inode i-number as the new current inode.
back Revert to the previously current inode.
clri i-number
Clear i-number.
lookup name
cd name
Find name in the current directory and make its inode the current
inode. Name may be a multi-component name or may begin with
slash to indicate that the root inode should be used to start the
lookup. If some component along the pathname is not found, the
last valid directory encountered is left as the active inode.
This command is valid only if the starting inode is a directory.
active
print Print out the active inode.
blocks Print out the block list of the active inode. Note that the
printout can become long for large files, since all indirect
block pointers will also be printed.
findblk disk_block_number ...
Find the inode(s) owning the specified disk block(s) number(s).
Note that these are not absolute disk blocks numbers, but offsets
from the start of the partition.
uplink Increment the active inode’s link count.
downlink
Decrement the active inode’s link count.
linkcount number
Set the active inode’s link count to number.
ls List the current inode’s directory entries. This command is
valid only if the current inode is a directory.
rm name
del name
Remove the entry name from the current directory inode. This
command is valid only if the current inode is a directory.
ln ino name
Create a link to inode ino under the name name in the current
directory inode. This command is valid only if the current inode
is a directory.
chinum dirslot inum
Change the i-number in directory entry dirslot to inum.
chname dirslot name
Change the name in directory entry dirslot to name. This command
cannot expand a directory entry. You can only rename an entry if
the name will fit into the existing directory slot.
chtype type
Change the type of the current inode to type. Type may be one
of: file, dir, socket, or fifo.
chmod mode
Change the mode bits of the current inode to mode. You cannot
change the file type with this subcommand; use chtype to do that.
chflags flags
Change the file flags of the current inode to flags.
chown uid
Change the owner of the current inode to uid.
chgrp gid
Change the group of the current inode to gid.
chgen gen
Change the generation number of the current inode to gen.
btime time
mtime time
ctime time
atime time
Change the creation (birth), modification, change, or access time
(respectively) on the current inode to time. Time should be in
the format YYYYMMDDHHMMSS[.nsec] where nsec is an optional
nanosecond specification. If no nanoseconds are specified, the
birthnsec, mtimensec, ctimensec, or atimensec field will be set
to zero. Note that btime is available on UFS2 file systems only.
quit, q, exit, <EOF>
Exit the program.
SEE ALSO
editline(3), fs(5), clri(8), fsck(8)
HISTORY
The fsdb utility uses the source code for fsck(8) to implement most of
the file system manipulation code. The remainder of fsdb first appeared
in NetBSD, written by John T. Kohl.
Peter Wemm ported it to FreeBSD.
BUGS
Manipulation of ‘‘short’’ symlinks has no effect. In particular, one
should not try changing a symlink’s type.
You must specify modes as numbers rather than symbolic names.
There are a bunch of other things that you might want to do which fsdb
does not implement.
WARNING
Use this tool with extreme caution--you can damage an FFS file system
beyond what fsck(8) can repair.