Clri zeros out the inodes with the specified inode number(s) on the filesystem residing on the given special_device . The fsck(8) utility is usually run after clri to reclaim the zero'ed inode(s) and the blocks previously claimed by those inode(s). Both read and write permission are required on the specified special_device .
The primary purpose of this routine is to remove a file which for some reason is not being properly handled by fsck(8). Once removed, it is anticipated that fsck(8) will be able to clean up the resulting mess.
The -w flag makes clri go through the motions, but will not write the zero'ed inode. The -y flag will perform the actions requested without requesting confirmation. The -b flag will set the filesystem blocksize to 512, rather than the default 1024 when indexing into the inodes.