How can I revert a package to a specific version on Gentoo? I'm a Debian user pretty much new to Gentoo. I wanted to install a specific version of a package namely the 1.39.0 version of dev-libs/boost, < But I already did "emerge dev-libs/boost" which installed me version 1.46.1-r1. machine ~ # emerge --search boost (...) * dev-libs/boost Latest version available: 1.46.1-r1 Latest version installed: 1.46.1-r1 Size of files: 41,016 kB Homepage: Description: Boost Libraries for C++ License: Boost-1.0 How can I revert this package back to version 1.39.0? Thank you in advance.

The boost packages are slotted, so you can actually have more than one version installed.

To emerge that version, simply issue:


emerge -a =dev-libs/boost-1.39.0


If you want to remove the newer version (quite dangerous, you could have a lot of stuff dependent on it), you could:


emerge --unmerge =dev-libs/boost-1.46.1-r1


and run a `revdep-rebuild` afterwards.

To switch your environment from one version to the other (if you kept both), use `eselect boost list/set`.