icheck" -- Command" "

i-node consistency check 

iicchheecckk [[--ss]] [[--bb _N _._._.]] [[ --vv ]] _f_i_l_e_s_y_s_t_e_m _._._.
Each block in a file system must be either free (i.e., in the free list) or allocated (i.e., associated with exactly one i-node). icheck examines each specified filesystem, printing block numbers that are claimed by more than one i-node, or claimed by both an i-node and the free list. It also checks for blocks that appear more than once in the block list of an i-node or in the free list.

The option -v (verbose) causes icheck to print a summary of block usage in the filesystem. The option -s causes icheck to ignore the free list, to note which blocks are claimed by i-nodes, and to rebuild the free list with the remainder. A list of block numbers may be submitted with the -b flag; icheck prints the data structure associated with each block as the file system is scanned.

The raw device should be used, and the filesystem should be unmounted if possible. If this is not possible (e.g., on the root file system) and the -s option is used, the system must be rebooted immediately to expunge the obsolete superblock.

The exit status bits for a bad return are as follows: 

00xx0011 Miscellaneous error (e.g. out of space)
00xx0022 Too hard to fix without human intervention
00xx0044 Bad free block
00xx0088 Missing blocks
00xx1100 Duplicates in free list
00xx2200 Bad block in free list

See Also

Diagnostics

The message ``dups in free'' indicates a block is in the free list more than once. ``bad freelist'' indicates the presence of bad blocks on the free list. A ``bad'' block is one that lies outside the bounds of the file system. A ``dup'' (duplicated) block is one associated with the free list and an i-node, or with more than one i-node. All the errors above must be corrected before the file system is mounted. ``bad ifree'' means allocated i-nodes are on the free i-node list; this is inconsequential.

A This command has largely been replaced by fsck.