Manual Pages  — CLRI

The clri utility zeroes out the inodes with the specified inode number(s) on the file system residing on the given special_device. The fsck(8) utility is usually run after clri to reclaim the zeroed 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.