DCHECK(8) System Manager's Manual DCHECK(8)
dcheck - file system directory consistency check
/etc/dcheck [ -i numbers ] [ filesystem ]
N.B.: Dcheck is obsoleted for normal consistency checking by fsck(8).
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.
Default file systems vary with installation.
fsck(8), icheck(8), fs(5), clri(8), ncheck(8)
When a file turns up for which the link-count and the number of direc-
tory 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
Since dcheck is inherently two-pass in nature, extraneous diagnostics
may be produced if applied to active file systems.
Dcheck is obsoleted by fsck and remains for historical reasons.
4th Berkeley Distribution 4 February 1983 DCHECK(8)