[src/trunk]: src/bin/sh Add an explanation of the error (warning)

[kre <kre%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/004d1b6cf3d0
branches:  trunk
changeset: 448096:004d1b6cf3d0
user:      kre <kre%NetBSD.org@localhost>
date:      Mon Jan 21 14:09:24 2019 +0000

description:
Add an explanation of the error (warning)
        RANDOM initialisation failed
when the shell might print after RANDOM has been reseeded
(which includes at sh startup) the next time RANDOM is accessed.
It indicates that /dev/urandom was not available or did not
provide data - in that case, sh uses a (weak) seed made out of
the pid and time (but otherwise nothing else changes).

diffstat:

 bin/sh/sh.1 |  10 +++++++++-
 1 files changed, 9 insertions(+), 1 deletions(-)

diffs (24 lines):

diff -r 333c7c47d1d5 -r 004d1b6cf3d0 bin/sh/sh.1
--- a/bin/sh/sh.1       Mon Jan 21 13:27:29 2019 +0000
+++ b/bin/sh/sh.1       Mon Jan 21 14:09:24 2019 +0000
@@ -1,4 +1,4 @@
-.\"    $NetBSD: sh.1,v 1.216 2018/12/12 20:22:43 kre Exp $
+.\"    $NetBSD: sh.1,v 1.217 2019/01/21 14:09:24 kre Exp $
 .\" Copyright (c) 1991, 1993
 .\"    The Regents of the University of California.  All rights reserved.
 .\"
@@ -4254,6 +4254,14 @@
 assigned before
 .Ev RANDOM
 is first accessed after shell initialization.
+Should the error message
+.Dq "RANDOM initialisation failed"
+appear on standard error, it indicates that the source
+of good random numbers was not available, and
+.Ev RANDOM
+has instead been seeded with a more predictable value.
+The following sequence of random numbers will
+not be as unpredictable as they otherwise would be.
 .It Ev SECONDS
 Returns the number of seconds since the current shell was started.
 If unset, it remains unset, and returns nothing, unless set again.