Use /dev/urandom (or corresponding file) by default in --both mode

[vbig.git] / vbig.1

diff --git a/vbig.1 b/vbig.1
index e6f230d80e8779572917a89c981d9a5141140e0d..43052d62680f9f0e6c601927afd11425743a8c1e 100644 (file)
--- a/vbig.1
+++ b/vbig.1
@@ -19,7 +19,7 @@
 .SH NAME
 vbig \- create or verify a large but pseudo-random file
 .SH SYNOPSIS
-\fBvbig \fR[\fB--seed \fRSEED\fR] \fB--both\fR|\fB--create\fR|\fB--verify\fR \fIPATH \fR[\fISIZE\fR]
+\fBvbig \fR[\fB--seed \fRSEED\fR] [\fB--both\fR|\fB--create\fR|\fB--verify\fR] \fIPATH \fR[\fISIZE\fR]
 .br
 \fBvbig --help
 .br
@@ -35,16 +35,30 @@ kilobytes, megabytes or gigabytes.
 The size is mandatory when creating a file but optional when verifying
 it, unless \-\-entire is specified.  If \fBSIZE\fR not specified when
 writing-then-verifying, it is as if \fB\-\-entire\fR was specified.
+.PP
+If no seed or seed file is specified:
+in \fB--both\fR mode a fresh random seed is read from the system's
+random number generator; in other modes a fixed default seed is used.
 .SH OPTIONS
 .TP
 .B --seed\fR, \fB-s \fISEED
 Specifies the random seed to use.
 Optional.
 .TP
+.B --seed-file\fR, \fB-S \fISEED-FILE
+Specifies wehre the random seed should be read from.  The
+first \fISEED-LENGTH\fR bytes will be used, or the whole file
+if it is shorter.
+.TP
+.B --seed-length\fR, \fB-L \fISEED-LENGTH
+Specifies the (maximum) seed length in bytes.
+Optional; default is 2048.
+.TP
 .B --both\fR, \fB-b
 Selects both mode.
 \fIPATH\fR will be filled with \fISIZE\fR psuedo-random bytes and
 then read to check that it contains the data just written.
+This is the default.
 .TP
 .B --create\fR, \fB-c
 Selects create mode.