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dcheck(8) [bsd man page]

DCHECK(8)						      System Manager's Manual							 DCHECK(8)

NAME
dcheck - file system directory consistency check SYNOPSIS
dcheck [ -i numbers ] [ filesystem ] DESCRIPTION
Dcheck reads the directories in a file system and compares the link-count in each i-node with the number of directory entries by which it is referenced. If the file system is not specified, a set of default file systems is checked. The -i flag is followed by a list of i-numbers; when one of those i-numbers turns up in a directory, the number, the i-number of the direc- tory, and the name of the entry are reported. The program is fastest if the raw version of the special file is used, since the i-list is read in large chunks. SEE ALSO
filsys(5), clri(8), fsck(8), icheck(8), ncheck(8) DIAGNOSTICS
When a file turns up for which the link-count and the number of directory entries disagree, the relevant facts are reported. Allocated files which have 0 link-count and no entries are also listed. The only dangerous situation occurs when there are more entries than links; if entries are removed, so the link-count drops to 0, the remaining entries point to thin air. They should be removed. When there are more links than entries, or there is an allocated file with neither links nor entries, some disk space may be lost but the situation will not degenerate. BUGS
Since dcheck is inherently two-pass in nature, extraneous diagnostics may be produced if applied to active file systems. Default file sys- tems vary with installation so dcheck should use fstab(5). 3rd Berkeley Distribution DCHECK(8)

Check Out this Related Man Page

icheck(8)						      System Manager's Manual							 icheck(8)

Name
       icheck - check inode consistency

Syntax
       /etc/icheck [ -s ]  [ -b numbers ] [ filesystem ]

Description
       The command is obsoleted for normal consistency checking by

       The command examines a file system, builds a bit map of used blocks, and compares this bit map against the free list maintained on the file
       system.	If the file system is not specified, a set of default file systems is checked.	The normal output of includes a report of:

       o   The total number of files and the numbers of regular, directory, block special and character special files.

       o   The total number of blocks in use and the numbers of single-, double-, and triple-indirect blocks and directory blocks.

       o   The number of free blocks.

       o   The number of blocks missing, that is, not in any file nor in the free list.

       The option causes to ignore the actual free list and reconstruct a new one by rewriting the super-block of the file system.  The file  sys-
       tem  should  be dismounted while this is done; if this is not possible (for example if the root file system has to be salvaged) care should
       be taken that the system is quiescent and that it is rebooted immediately afterwards so that the old, bad in-core copy of  the  super-block
       will not continue to be used.  Notice also that the words in the super-block which indicate the size of the free list and of the i-list are
       believed.  If the super-block has been curdled these words will have to be patched.  The option causes the normal output reports to be sup-
       pressed.

       Following the option is a list of block numbers; whenever any of the named blocks turns up in a file, a diagnostic is produced.

       The command is faster if the raw version of the special file is used, since it reads the i-list many blocks at a time.

Diagnostics
       For  duplicate  blocks  and  bad  blocks  (which lie outside the file system) announces the difficulty, the i-number, and the kind of block
       involved.  If a read error is encountered, the block number of the bad block is printed and considers it to  contain  0.   `Bad	freeblock'
       means that a block number outside the available space was encountered in the free list.	`n dups in free' means that n blocks were found in
       the free list which duplicate blocks either in some file or in the earlier part of the free list.

Restrictions
       Since is inherently two-pass in nature, extraneous diagnostics may be produced if applied to active file systems.

       It believes even preposterous super-blocks and consequently can get core images.

Files
       Default file systems vary with installation.

See Also
       fs(5), clri(8), dcheck(8), fsck(8), ncheck(8)

																	 icheck(8)

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