Re: incompatible environment variable names

[Steven Collins <spc dot for dot nbc at gmail dot com>]

On Wed, Aug 4, 2010 at 10:23, Nellis, Kenneth wrote:
> I came across an interesting (IMHO) incompatibility between
> Windows and bash environment variable names.
>
> I have a Windows environment variable as such:
>
> C:\>set QNX_VISUAL_C++_PATH
> QNX_VISUAL_C++_PATH=C:\Program Files\Orbital Qnx VisualC++ IDE
>
> So, Windows has no problem with + symbols in variable names, but
> bash does, kinda sorta:
>
> Cygwin> printenv QNX_VISUAL_C++_PATH
> C:\Program Files\Orbital Qnx VisualC++ IDE
> Cygwin> cygpath "$QNX_VISUAL_C++_PATH"
> ++_PATH
> Cygwin> echo "$QNX_VISUAL_C++_PATH"
> ++_PATH
> Cygwin> echo ${QNX_VISUAL_C++_PATH}
>
> Cygwin> cygpath "$(printenv QNX_VISUAL_C++_PATH)"
> /cygdrive/c/Program Files/Orbital Qnx VisualC++ IDE
> Cygwin>
>
> So, it seems that I can only access the value of the variable
> through printenv, and then cygpath does what I need, but I can't
> then assign it back to the environment variable:
>
> Cygwin> export QNX_VISUAL_C++_PATH="$(cygpath "$(printenv QNX_VISUAL_C++_PATH)")"
> -bash: export: `QNX_VISUAL_C++_PATH=/cygdrive/c/Program Files/Orbital Qnx VisualC++ IDE': not a valid identifier
> Cygwin>
>
> I probably need to give up on this, but felt like sharing my misery.
>
> --Ken Nellis
>

>From the bash man page:

<bashManPage>
<snip/>

DEFINITIONS
       The following definitions are used throughout the rest of this document.
       blank  A space or tab.
       word   A sequence of characters considered as a single unit by
the shell.  Also known as a token.
       name   A word consisting only of alphanumeric characters and
underscores, and beginning with an alphabetic character or an
underscore.  Also referred to as an identifier.

<snip/>


PARAMETERS
       A parameter is an entity that stores values.  It can be a name,
a number, or one of the special characters listed below under Special
Parameters.  A variable is a parameter denoted by a name.  A variable
has a value and zero or more attributes.  Attributes are  assigned
using
       the declare builtin command (see declare below in SHELL BUILTIN
COMMANDS).

<snip/>
</bashManPage>

Hench bash does not support the plus character in a variable name and
no amount of finagling is going to fix it.

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