FSDB(8) | System Manager's Manual | FSDB(8)

# NAME

fsdb — FFS debugging/editing tool

# SYNOPSIS

fsdb | [-dFn] -f fsname

# DESCRIPTION

fsdb 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 filesystem (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 -d option enables additional debugging output (which comes primarily from fsck(8)-derived code).

The -F option indicates that filesystem is a file system image, rather than a raw character device. It will be accessed ‘as-is', and no attempts will be made to read a disklabel.

The -n option disables writing to the device, preventing any changes from being made to the filesystem.

# 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
  Clear the current inode.

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.

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.

blks
  List the current inode's blocks numbers.

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.

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.

mtime time
ctime time
atime time
  Change the 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 mtimensec, ctimensec, or atimensec field will be set to zero.

quit, q, exit, <EOF>
  Exit the program.

# SEE ALSO

editline(3), fs(5), clri(8), fsck(8)

# HISTORY

fsdb uses the source code for fsck(8) to implement most of the file system manipulation code. The remainder of fsdb first appeared in NetBSD 1.1.

# WARNING

Use this tool with extreme caution -- you can damage an FFS file system beyond what fsck(8) can repair.

# BUGS

Manipulation of “short” symlinks doesn't work (in particular, don't 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 doesn't implement.

January 3, 2004 | NetBSD 6.0