man/man8/check.8

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NAME            check -- file system consistency check
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SYNOPSIS        check\b\b\b\b\b_____ [ filesystem [ blockno\e91\e8 ... ] ]
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DESCRIPTION     check\b\b\b\b\b_____
will examine a file system,
build a bit map of used blocks,
and compare this bit map against
the bit map maintained on the file system.
If the file system is not specified,
a check of all
of the normally mounted file systems
is performed.
Output includes the number of files on the file system,
the number of these that are 'large', the number
of indirect blocks,
the number
of used blocks, and the number of free blocks.
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check\b\b\b\b\b_____ works by examining the i-nodes
on the file system and is entirely
independent of its directory hierarchy.
The file system may be,
but need not be, mounted.

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FILES           /dev/rf?,
/dev/rk?,
/dev/rp?
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SEE ALSO        find(I), ds(I)
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DIAGNOSTICS     Diagnostics are produced for
blocks missing, duplicated, and bad block addresses.
Diagnostics are also produced for block numbers passed as parameters.
In each case, the block number, i-number, and
block class (i\b_ = inode, x\b_ indirect, f\b_ free) is printed.
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BUGS            The
checking process is two pass in nature.
If checking is done on an active file system,
extraneous diagnostics may occur.