Command Section
FSDB(8)                 FreeBSD System Manager's Manual                FSDB(8)

     fsdb - FFS debugging/editing tool

     fsdb [-d] [-f] [-r] fsname

     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.

     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.

     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.

             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.

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

     The fsdb utility appeared in 4.3BSD-Tahoe.  It used the source code for
     fsck(8) to implement most of the file system manipulation code.  The
     remainder of fsdb appeared in NetBSD 1.1 written by John T. Kohl.  It
     first appeared in FreeBSD 2.1.5 ported by Peter Wemm.

     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.

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

FreeBSD 11.1-RELEASE-p4         October 3, 2016        FreeBSD 11.1-RELEASE-p4
Command Section