\"
\" This file is part of vbig.
\" Copyright (C) 2011 Richard Kettlewell
\"
\" This program is free software: you can redistribute it and/or modify
\" it under the terms of the GNU General Public License as published by
\" the Free Software Foundation, either version 3 of the License, or
\" (at your option) any later version.
\"
\" This program is distributed in the hope that it will be useful,
\" but WITHOUT ANY WARRANTY; without even the implied warranty of
\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
\" GNU General Public License for more details.
\"
\" You should have received a copy of the GNU General Public License
\" along with this program.  If not, see <http://www.gnu.org/licenses/>.
\"
.TH vbig 1
.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]
.br
\fBvbig --help
.br
\fBvbig --version
.SH DESCRIPTION
\fBvbig\fR creates a file of specified size full of predictable
psuedo-random data, and/or verifies that it has the expected contents.
The intended use is to test whether storage media really do what they
say on the tin.
.PP
\fISIZE\fR may end with \fBK\fR, \fBM\fR or \fBG\fR to select (binary)
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.
.SH OPTIONS
.TP
.B --seed\fR, \fB-s \fISEED
Specifies the random seed to use.
Optional.
.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.
\fIPATH\fR will be filled with \fISIZE\fR psuedo-random bytes.
.TP
.B --verify\fR, \fB-v
Selects verify mode.
Checks that \fIPATH\fR has exactly the contents that would be produced
by the equivalent \fB--create\fR call.
.TP
.B --flush\fR, \fB-f
Flush cached data after creating the file or before verifying it.
On some platforms, only root can use this option.
.TP
.B --entire\fR, \fB-e
When writing, keep going until the device is full (No space left
on device).  When reading, keep going until the end of the file
or device.  \fISIZE\fR should not be specified.  The actual size
written or verified will be printed to stdout.
.TP
.B --help\fR, \fB-h
Displays a usage message.
.TP
.B --version\fR, \fB-h
Displays the version strings.
.SH AUTHOR
Richard Kettlewell <rjk@greenend.org.uk>