32v 1m dcheck
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DCHECK(1M) UNIX Programmer's Manual DCHECK(1M)
dcheck - file system directory consistency check
dcheck [ -i numbers ] [ filesystem ]
_D_c_h_e_c_k 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 directory, 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.
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.
Since _d_c_h_e_c_k is inherently two-pass in nature, extraneous diagnostics may be produced if applied to active file sys- tems.