[src/trunk]: src/bin/sh At the suggestion of Matthew Sporleder (on current-us...

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

details:   https://anonhg.NetBSD.org/src/rev/d25f5d2d6887
branches:  trunk
changeset: 822454:d25f5d2d6887
user:      kre <kre%NetBSD.org@localhost>
date:      Mon Mar 20 22:17:56 2017 +0000

description:
At the suggestion of Matthew Sporleder (on current-users@) reword some
of the description of arithmetic expressions to make it a bit more
human friendly.

While here fix a few other minor errors, and bump date.

diffstat:

 bin/sh/sh.1 |  30 ++++++++++++++++++++----------
 1 files changed, 20 insertions(+), 10 deletions(-)

diffs (74 lines):

diff -r cc1935493eb0 -r d25f5d2d6887 bin/sh/sh.1
--- a/bin/sh/sh.1       Mon Mar 20 22:05:27 2017 +0000
+++ b/bin/sh/sh.1       Mon Mar 20 22:17:56 2017 +0000
@@ -1,4 +1,4 @@
-.\"    $NetBSD: sh.1,v 1.126 2017/03/20 11:26:07 kre Exp $
+.\"    $NetBSD: sh.1,v 1.127 2017/03/20 22:17:56 kre Exp $
 .\" Copyright (c) 1991, 1993
 .\"    The Regents of the University of California.  All rights reserved.
 .\"
@@ -31,7 +31,7 @@
 .\"
 .\"    @(#)sh.1        8.6 (Berkeley) 5/4/95
 .\"
-.Dd February 1, 2017
+.Dd March 20, 2017
 .Dt SH 1
 .ds flags abCEeFfhnuvxIimpqV
 .Os
@@ -1235,13 +1235,23 @@
 .Pp
 .Dl $((expression))
 .Pp
-The expression is treated as if it were in double quotes, except
-that a double quote inside the expression is not treated specially.
+The expression in an arithmetic expansion is treated as if it were in
+double quotes, except that a double quote character inside the expression
+is just a normal character (it quotes nothing.)
 The shell expands all tokens in the expression for parameter expansion,
-command substitution, and quote removal.
+command substitution, and quote removal (the only quoting character is
+the backslash
+.Sq \&\e ,
+and only when followed by another
+.Sq \&\e ,
+a dollar sign
+.Sq \&$ ,
+a backquote
+.Sq \&`
+or a newline.)
 .Pp
-Next, the shell treats this as an arithmetic expression and
-substitutes the value of the expression.
+Next, the shell evaluates the expanded result as an arithmetic expression
+and substitutes the calculated value of that expression.
 .Pp
 Arithmetic expressions use a syntax similar to that
 of the C language, and are evaluated using the
@@ -1250,7 +1260,7 @@
 .Tn POSIX ,
 which requires only
 .Ql long
-arithmetic).
+arithmetic.)
 Shell variables may be referenced by name inside an arithmetic
 expression, without needing a
 .Dq \&$
@@ -1595,7 +1605,7 @@
 With
 .Fl n
 the specified names are un-exported.
-Variables can also be un-exported using the unset builtin command.
+Variables can also be un-exported using the unset built in command.
 With
 .Fl x
 (exclude) the specified names are marked not to be exported,
@@ -2216,7 +2226,7 @@
 Once waited upon, by specific process number or job-id,
 or by a
 .Ic wait
-with no argumentss,
+with no arguments,
 knowledge of the child is removed from the system,
 and it cannot be waited upon again.
 .El