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VENTI(1)		    General Commands Manual		      VENTI(1)

       read, write, copy - simple Venti	clients

       venti/read [ -h host ] [	-t type	] score
       venti/write [ -z	] [ -h host ] [	-t type	]
       venti/copy [ -fimrVv ] [	-t type	] srchost dsthost score

       Venti  is  a  SHA1-addressed  block storage server.  See	venti(7) for a
       full introduction.

       Read reads a block with the given  score	 and  numeric  type  from  the
       server  host and	prints the block to standard output.  If the -h	option
       is omitted, read	consults the environment variable $venti for the  name
       of  the	Venti server.  If the -t option	is omitted, read will try each
       type, one at a time, until it finds one that works.  It prints the cor-
       responding  read	 -t  command to	standard error to indicate the type of
       the block.

       Write writes at most 56 kilobytes of data from standard	input  to  the
       server  host and	prints the resulting score to standard output.	If the
       -t option is omitted, write uses	type 0,	denoting a data	block.	If the
       -z option is given, write zero truncates	the block before writing it to
       the server.

       Copy expects score to be	the score of a VtRoot block.   It  copies  the
       entire tree of blocks reachable from the	root block from	the server sr-
       chost to	the server dsthost.

       Venti's blocks are arranged in a	directed acyclic graph (see venti(6));
       there may be multiple paths from	a root score to	an interior block (for
       example,	if the same file contents are stored under multiple  names  in
       an  archive).   Copy  runs  more	efficiently if it does not copy	blocks
       (and all	their children)	multiple times.	 The -f	option causes copy  to
       assume  that if a block already exists on the destination Venti server,
       all its children	also exist and need not	be considered.	The -m	option
       causes  copy  to	maintain an in-memory list of blocks it	has copied and
       avoid considering the same block	multiple times.	 The -f	option is only
       useful  if  the	destination Venti server is known not to have lost any
       blocks due to disk corruption or	other failures.	 The -m	option is only
       useful if enough	memory is available to hold the	block list, which typ-
       ically requires about 1%	of the total number of bytes being copied.

       The -i and -r options control copy's reaction to	 errors	 reading  from
       srchost.	  Copy	always prints information to standard error about each
       read error.  By default,	copy exits after printing the first error.  If
       the -i option is	given, read errors are ignored.	 This is dangerous be-
       havior because it breaks	the assumption made by `fast' mode.  If	the -r
       option  is  given,  copy	 replaces  pointers  to	unreadable blocks with
       pointers	to the zero block.  It writes the new root score  to  standard
       output.	 The  -v option	prints scores as it copies them, total writes,
       and other debugging information.	 The -V	option prints debugging	infor-
       mation about the	Venti protocol messages	send/received.


       vac(1),	venti(3),  vacfs(4),  venti(7),	 vbackup(8),  venti(8),	venti-

       There should be programs	to read	and write venti	files and directories.



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