variable override syntax, where is it documented?

variable override syntax, where is it documented?

[Bernd]

I just found out that I can ovverride the line

hostname = "${MACHINE}"

in base-files simply by assigning a value to

hostname_pn-base-files

in my configuration file and it will re-assign it with a higher
priority than "=".

Now I wonder where this kind of black magic is documented, I don't
seem to be able to locate any document that explains the "_pn-" syntax
and I wonder if there are even more such tricks that could be useful
and am looking for a document that explains them all. Is there such a
thing?

- Bernd

Re: variable override syntax, where is it documented?

[Alexander Kanavin]

On 12/06/2017 10:58 AM, Bernd wrote:
> I just found out that I can ovverride the line
> 
> hostname = "${MACHINE}"
> 
> in base-files simply by assigning a value to
> 
> hostname_pn-base-files
> 
> in my configuration file and it will re-assign it with a higher
> priority than "=".
> 
> Now I wonder where this kind of black magic is documented, I don't
> seem to be able to locate any document that explains the "_pn-" syntax
> and I wonder if there are even more such tricks that could be useful
> and am looking for a document that explains them all. Is there such a
> thing?

Yes, of course. This:

http://www.yoctoproject.org/docs/latest/ref-manual/ref-manual.html#var-OVERRIDES

and this:

http://www.yoctoproject.org/docs/2.5/bitbake-user-manual/bitbake-user-manual.html#conditional-syntax-overrides


Alex