[PATCH 1/2] doc: add note about characters like hyphens in variable names

[Sascha Hauer]

On Tue, Nov 10, 2020 at 04:34:29PM +0100, Ahmad Fatoum wrote:
> The mismatch between the allowed characters in shell variables and
> device parameters is a common pitfall, especially because device
> tree node names often have hyphens in them, which is disallowed by
> hush.
> 
> While such variables can be read by the ${variable-example}, setting
> them is only possible with the setenv command. Reflect this in the
> documentation.
> 
> Signed-off-by: Ahmad Fatoum <a.fatoum at pengutronix.de>
> ---
> Cc: Matthias Fend <Matthias.Fend at wolfvision.net>
> ---
>  Documentation/user/driver-model.rst | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)

Applied, thanks

Sascha

> 
> diff --git a/Documentation/user/driver-model.rst b/Documentation/user/driver-model.rst
> index a0fd3e99b55b..c543d6d9c410 100644
> --- a/Documentation/user/driver-model.rst
> +++ b/Documentation/user/driver-model.rst
> @@ -88,7 +88,14 @@ The parameters can be used as shell variables:
>  .. code-block:: sh
>  
>    eth0.ipaddr=192.168.23.15
> -  echo "my current ip is: $eth0.ipaddr"
> +  echo "my current ip is: ${eth0.ipaddr}"
> +
> +.. note::
> +
> +  Hush shell syntax for defining and setting variables is the same, so
> +  some characters such as hyphens are not allowed on the left hand side
> +  of a shell variable assignment. :ref:`command_setenv`, if enabled,
> +  can still be used to write such a variable though.
>  
>  device variables may have a type, so assigning wrong values may fail:
>  
> -- 
> 2.28.0
> 
> 
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> 

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