I’m often looking for the right command when i start with Gentoo, so I’ve post here a shortlist of commands that i found on some sites. The first entire will recompile all ports, so keep in mind that will take a long time.
Chances are if you have the know how to use Gentoo and made it thus far to get it installed you probably don’t need this tutorial, but it’s good to have as much documentation as possible. Emerge makes installing easy, just as apt-get would be Ubuntu, but in emerge we can install source built applications rather than binary applications, thus is the Gentoo way. And along with that is many more options for these packages. This tutorial will just cover the basics.
Emerge searches through the Portage Tree for applications. The Portage tree is a collection of ebuilds files that contain all information Portage needs to maintain software (install, search, query, …). These ebuilds reside in /usr/portage by default.
Whenever you ask Portage to perform some action regarding software titles, it will use the ebuilds on your system as a base. It is therefore important that you regularly update the ebuilds on your system so Portage knows about new software, security updates, etc.