sh: Add details about importing the environment and initializing OPTIND.

This commit is contained in:
jilles 2015-02-22 21:32:57 +00:00
parent 2a7963a7ec
commit d2889adcc5

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@ -32,7 +32,7 @@
.\" from: @(#)sh.1 8.6 (Berkeley) 5/4/95
.\" $FreeBSD$
.\"
.Dd November 14, 2014
.Dd February 22, 2015
.Dt SH 1
.Os
.Sh NAME
@ -1196,17 +1196,18 @@ command is implemented as a special built-in command.
.Ss Variables and Parameters
The shell maintains a set of parameters.
A parameter
denoted by a name is called a variable.
denoted by a name
(consisting solely
of alphabetics, numerics, and underscores,
and starting with an alphabetic or an underscore)
is called a variable.
When starting up,
the shell turns all the environment variables into shell
the shell turns all environment variables with valid names into shell
variables.
New variables can be set using the form
.Pp
.D1 Ar name Ns = Ns Ar value
.Pp
Variables set by the user must have a name consisting solely
of alphabetics, numerics, and underscores.
The first letter of a variable name must not be numeric.
A parameter can also be denoted by a number
or a special character as explained below.
.Pp
@ -1369,6 +1370,10 @@ This variable overrides the
.Va MAIL
setting.
There is a maximum of 10 mailboxes that can be monitored at once.
.It Va OPTIND
The index of the next argument to be processed by
.Ic getopts .
This is initialized to 1 at startup.
.It Va PATH
The default search path for executables.
See the
@ -2297,6 +2302,8 @@ If an invalid option is encountered,
is set to
.Ql \&? .
It returns a false value (1) when it encounters the end of the options.
A new set of arguments may be parsed by assigning
.Li OPTIND=1 .
.It Ic hash Oo Fl rv Oc Op Ar command ...
The shell maintains a hash table which remembers the locations of commands.
With no arguments whatsoever, the
@ -2771,7 +2778,7 @@ This is inherited by children of the shell, and is used in the history
editing modes.
.El
.Pp
Additionally, all environment variables are turned into shell variables
Additionally, environment variables are turned into shell variables
at startup,
which may affect the shell as described under
.Sx Special Variables .