man: import changes from plan 9

R=rsc
CC=plan9port.codebot
http://codereview.appspot.com/4559071

man/man8/venti-backup.8

@@ -5,7 +5,7 @@ rdarena, wrarena \- copy arenas between venti servers
 .PP
 .B venti/rdarena
 [
-.B -v
+.B -qv
 ]
 .I arenapart
 .I arenaname
@@ -34,7 +34,9 @@ and writes this arena to standard output.
 This command is typically used to back up an arena to external media.
 The
 .B -v
-option generates more verbose output on standard error.
+option generates more verbose output on standard error;
+.B -q
+generates only errors on standard error.
 .PP
 .I Wrarena
 writes the blocks contained in the arena
@@ -97,10 +99,14 @@ awk '/^end offset/ { print $3 }' offset >last
 Of course, one would need to add wrapper code to keep track
 of which arenas have been processed.
 See
-.B /sys/src/cmd/venti/backup.example
+.B /sys/src/cmd/venti/words/backup.example
 for a version that does this.
 .SH SOURCE
 .B \*9/src/cmd/venti/srv
 .SH SEE ALSO
 .IR venti (7),
 .IR venti (8)
+.SH BUGS
+.I Wrarena
+can't read a pipe or network connection containing an arena;
+it needs a file already containing the entire arena.