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.TH VENTI 1
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.SH NAME
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read, write, copy \- simple Venti clients
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.SH SYNOPSIS
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.B venti/read
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[
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.B -h
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.I host
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]
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[
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.B -t
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.I type
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]
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.I score
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.br
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.B venti/write
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[
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.B -z
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]
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[
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.B -h
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.I host
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]
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[
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.B -t
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.I type
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]
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.br
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.B venti/copy
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[
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.B -fir
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]
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[
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.B -t
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.I type
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]
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.I srchost
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.I dsthost
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.I score
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[
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.I type
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]
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.SH DESCRIPTION
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Venti is a SHA1-addressed block storage server.
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See
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.IR venti (6)
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for a full introduction.
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.PP
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.I Read
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reads a block with the given
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.I score
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and numeric
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.I type
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from the server
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.I host
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and prints the block to standard output.
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If the
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.B -h
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option is omitted,
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.I read
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consults the environment variable
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.B $venti
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for the name of the Venti server.
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If the
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.B -t
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option is omitted,
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.I read
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will try each type, one at a time, until it finds
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one that works.
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It prints the corresponding
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.B read
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.B -t
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command to standard error
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to indicate the type of the block.
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.PP
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.I Write
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writes at most 56 kilobytes of data from standard input
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to the server
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.I host
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and prints the resulting score to standard output.
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If the
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.B -t
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option is omitted,
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.I write
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uses type 0,
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denoting a data block.
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If the
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.B -z
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option is given,
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.I write
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zero truncates the block before writing it to the server.
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.PP
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.I Copy
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expects
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.I score
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to be the score of a
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.B VtRoot
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block.
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It copies the entire tree of blocks reachable from
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the root block from the server
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.I srchost
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to the server
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.IR dsthost .
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.PP
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The
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.B -f
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option causes
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.I copy
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to run in `fast' mode,
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assuming that if a block already exists on the
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destination Venti server, all its children also
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exist and need not be checked.
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.PP
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The
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.B -i
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and
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.B -r
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options control
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.IR copy 's
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reaction to errors reading
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from
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.IR srchost .
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.I Copy
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always prints information to standard error
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about each read error.
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By default,
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.I copy
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exits after printing the first error.
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If the
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.B -i
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option is given, read errors are ignored.
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This is dangerous behavior because it breaks the
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assumption made by `fast' mode.
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If the
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.B -r
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option is given,
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.I copy
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replaces pointers to unreadable blocks with
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pointers to the zero block.
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It writes the new root score to standard output.
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.SH SOURCE
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.B /sys/src/cmd/venti
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.SH SEE ALSO
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.IR vac (1),
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.IR venti (2),
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.IR vacfs (4),
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.IR venti (6),
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.IR venti (8),
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.IR venti-backup (8),
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.IR venti-fmt (8)
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.SH BUGS
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There should be programs to read and write
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venti files and directories.