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.