Re: [gentoo-user] question about portage capabilities

[Jorge Morais]

On Sat, 18 Apr 2009 21:33:18 -0400
Denis <denis.che@×××××.com> wrote:

> Hello all,
>
> I am using a package called Rasmol, which is used for visualization of
> molecular structures.  This software uses a certain table for atomic
> sizes, and I need to change some values in that table - it is stored
> in a header file within Rasmol source code.  There is an ebuild for
> Rasmol, and it works fine - but what I'm wondering is how I can tell
> portage to STOP once it unpacks Rasmol in the temporary work directory
> - so I can tweak some things in the source code - and then resume the
> build, using what's already in the work directory.  Looking at a
> manpage for emerge, I didn't immediately get any creative ideas, but
> might someone offer some advice for how to accomplish this?

man ebuild.

I assume you are talking of sci-chemistry/rasmol.
Then you can accomplish your hack with
ebuild /usr/portage/sci-chemistry/rasmol/rasmol-2.7.2.1.1-r1.ebuild unpack
<tweak>
ebuild /usr/portage/sci-chemistry/rasmol/rasmol-2.7.2.1.1-r1.ebuild install

But I am not sure this is a clean way to achieve your goal.
The standard way would be to write a patch, and modify the ebuild
to apply your patch. Alternatively, you can apply the patch to the distfile,
and modify the ebuild to use the new distfile.

Do you know how to write a patch?

Note: if you are going to modify your ebuild, it is a good idea to
put it in an overlay
It would be something like this
mkdir --parents /usr/local/denisoverlay/sci-chemistry/rasmol
cp -rv /usr/portage/sci-chemistry/rasmol/* /usr/local/denisoverlay/sci-chemistry/rasmol/
tweak files in /usr/portage/sci-chemistry/rasmol to your heart's content.
Add "/usr/local/denisoverlay" to the variable PORTDIR_OVERLAY in /etc/make.conf
For example:

PORTDIR_OVERLAY="/usr/local/denisoverlay"

-- 
Software is like sex: it is better when it is free. --Linus Torvalds