As per the current Portage specification, ebuild repositories (a.k.a. overlays) can be managed via file collections under /etc/portage/repos.conf/, via the new plug-in sync system.

The overlay can be enabled via the repository extension of the Gentoo eselect utility.

emerge --ask --noreplace --verbose eselect-repository
eselect repository enable science

To disable and remove the overlay, run:

eselect repository disable science
eselect repository remove science

To enable the overlay without the need for dedicated repository software, you need to have git installed:

emerge --ask --noreplace --verbose dev-vcs/git

Then you can simply download the science repository configuration file, science.conf:

wget https://gitweb.gentoo.org/proj/sci.git/plain/metadata/science.conf \
	-O /etc/portage/repos.conf/science

To disable and remove the overlay, run:

rm /etc/portage/repos.conf/science
rm /var/db/repos/science -rf

You can also install the overlay via the layman overlay manager.

emerge --ask --noreplace --verbose app-portage/layman
layman --add science

To delete the overlay, run:

layman --delete science

To start using the overlay you now only need to get the newest files, via:

emerge --sync science

To be able to install ::science packages you need to make sure that you are accepting the ~${ARCH} keyword for your respective architecture. This may already be the case globally on your system, and you can check whether this is the case by running:

grep "~$(portageq envvar ARCH)" /etc/portage/make.conf

If the above returns empty, you will need to instruct Portage to accept ~${ARCH} packages.

This can be done for ::science specifically:

mkdir -p /etc/portage/package.accept_keywords
printf '*/*::science ~%s' "$(portageq envvar ARCH)" >> /etc/portage/package.accept_keywords/science

If the above fails with mkdir: cannot create directory ‘/etc/portage/package.accept_keywords’: File exists this means you are using a file and not a directory, and you can instead run:

printf '*/*::science ~%s' "$(portageq envvar ARCH)" >> /etc/portage/package.accept_keywords

Alternatively, and only if you know what you are doing, you can accept ~${ARCH} packages globally:

printf 'ACCEPT_KEYWORDS="~%s"' "$(portageq envvar ARCH)" >> /etc/portage/make.conf

The downside of this approach is potentially higher instability, the advantage is that often ::science packages require ~${ARCH} packages from ::gentoo as well.

If you fork, we will merge!
We welcome new contributors and are happy to include new packages.

• Current open bugs

For a brief introduction please see our contributing guide. Further helpful resources are:

• Gentoo Developers Manual - https://devmanual.gentoo.org/ (taking precedence over any other information found here)
• Contributing to Gentoo - https://wiki.gentoo.org/wiki/Contributing_to_Gentoo

Additionally, please make sure to add the Science Project as an additional maintainer to any new packages you submit. For an example, take a look at the metadata for the Numba package - dev-python/numba/metadata.xml

You can ask for help on Libera IRC in #gentoo-science. Alternatively you can report bugs on the Gentoo Bugzilla.