openssl/doc/man1/rand.pod
Rich Salz 3ee1eac27a Standardize apps use of -rand, etc.
Standardized the -rand flag and added a new one:
    -rand file...
            Always reads the specified files
    -writerand file
            Always writes to the file on exit

For apps that use a config file, the RANDFILE config parameter reads
the file at startup (to seed the RNG) and write to it on exit if
the -writerand flag isn't used.

Ensured that every app that took -rand also took -writerand, and
made sure all of that agreed with all the documentation.

Fix error reporting in write_file and -rand

Reviewed-by: Paul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/3862)
2017-07-16 19:20:45 -04:00

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=pod
=head1 NAME
rand - generate pseudo-random bytes
=head1 SYNOPSIS
B<openssl rand>
[B<-help>]
[B<-out> I<file>]
[B<-rand file...>]
[B<-writerand file>]
[B<-base64>]
[B<-hex>]
I<num>
=head1 DESCRIPTION
The B<rand> command outputs I<num> pseudo-random bytes after seeding
the random number generator once. As in other B<openssl> command
line tools, PRNG seeding uses the file I<$HOME/>B<.rnd> or B<.rnd>
in addition to the files given in the B<-rand> option. A new
I<$HOME>/B<.rnd> or B<.rnd> file will be written back if enough
seeding was obtained from these sources.
=head1 OPTIONS
=over 4
=item B<-help>
Print out a usage message.
=item B<-out file>
Write to I<file> instead of standard output.
=item B<-rand file...>
A file or files containing random data used to seed the random number
generator.
Multiple files can be specified separated by an OS-dependent character.
The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for
all others.
=item [B<-writerand file>]
Writes random data to the specified I<file> upon exit.
This can be used with a subsequent B<-rand> flag.
=item B<-base64>
Perform base64 encoding on the output.
=item B<-hex>
Show the output as a hex string.
=back
=head1 SEE ALSO
L<RAND_bytes(3)>
=head1 COPYRIGHT
Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.
Licensed under the OpenSSL license (the "License"). You may not use
this file except in compliance with the License. You can obtain a copy
in the file LICENSE in the source distribution or at
L<https://www.openssl.org/source/license.html>.
=cut