1 .TH VENTI 1
2 .SH NAME
3 read, write, copy \- simple Venti clients
4 .SH SYNOPSIS
5 .B venti/read
6 [
7 .B -h
8 .I host
9 ]
10 [
11 .B -t
12 .I type
13 ]
14 .I score
15 .br
16 .B venti/write
17 [
18 .B -z
19 ]
20 [
21 .B -h
22 .I host
23 ]
24 [
25 .B -t
26 .I type
27 ]
28 .br
29 .B venti/copy
30 [
31 .B -fir
32 ]
33 [
34 .B -t
35 .I type
36 ]
37 .I srchost
38 .I dsthost
39 .I score
40 .SH DESCRIPTION
41 Venti is a SHA1-addressed block storage server.
42 See 
43 .IR venti (7)
44 for a full introduction.
45 .PP
46 .I Read
47 reads a block with the given
48 .I score
49 and numeric
50 .I type 
51 from the server
52 .I host
53 and prints the block to standard output.
54 If the
55 .B -h
56 option is omitted,
57 .I read
58 consults the environment variable
59 .B $venti
60 for the name of the Venti server.
61 If the
62 .B -t
63 option is omitted,
64 .I read
65 will try each type, one at a time, until it finds
66 one that works.
67 It prints the corresponding
68 .B read
69 .B -t
70 command to standard error
71 to indicate the type of the block.
72 .PP
73 .I Write
74 writes at most 56 kilobytes of data from standard input 
75 to the server
76 .I host
77 and prints the resulting score to standard output.
78 If the
79 .B -t
80 option is omitted,
81 .I write
82 uses type 0,
83 denoting a data block.
84 If the
85 .B -z
86 option is given,
87 .I write
88 zero truncates the block before writing it to the server.
89 .PP
90 .I Copy
91 expects
92 .I score
93 to be the score of a 
94 .B VtRoot
95 block.
96 It copies the entire tree of blocks reachable from
97 the root block from the server
98 .I srchost
99 to the server
100 .IR dsthost .
101 .PP
102 The
103 .B -f
104 option causes
105 .I copy
106 to run in `fast' mode,
107 assuming that if a block already exists on the
108 destination Venti server, all its children also
109 exist and need not be checked.
110 .PP
111 The
112 .B -i
113 and
114 .B -r
115 option control
116 .IR copy 's
117 reaction to errors reading
118 from
119 .IR srchost .
120 .I Copy
121 always prints information to standard error
122 about each read error.
123 By default,
124 .I copy
125 exits after printing the first error.
126 If the
127 .B -i
128 option is given, read errors are ignored.
129 This is dangerous behavior because it breaks the 
130 assumption made by `fast' mode.
131 If the
132 .B -r
133 option is given, 
134 .I copy
135 replaces pointers to unreadable blocks with
136 pointers to the zero block.
137 It writes the new root score to standard output.
138 .SH SOURCE
139 .B \*9/src/cmd/venti
140 .SH SEE ALSO
141 .IR vac (1),
142 .IR venti (3),
143 .IR vacfs (4),
144 .IR venti (7),
145 .IR vbackup (8),
146 .IR venti (8)
147 .SH BUGS
148 There should be programs to read and write
149 venti files and directories.