emerge

emerge is a verb meaning to come into view or existence, or to come out from concealment. It derives from Latin emergere, from ex- meaning out and mergere meaning to dip or sink. In computing, emerge is the name of a widely used package management command in Gentoo Linux. It is the primary interface to Portage, the Gentoo package management framework. Through the emerge command, users fetch, configure, compile, and install software from the Portage tree, which contains ebuild scripts describing how to build each package.

Common usage includes updating the portage tree with emerge --sync; upgrading installed packages with emerge --update @world or emerge -uDv @world; performing a dry run with emerge --pretend; and removing unused dependencies with emerge --depclean (where available via the app-portage/gentoolkit). Packages are described by atoms and are controlled by USE flags, which enable or disable optional features. The build process is largely from source, though Gentoo can be configured to use prebuilt binary packages when available, improving installation speed. Emerge handles dependency resolution, conflict management, and the maintenance of a local package database. It also interacts with configuration files such as /etc/portage/make.conf, which sets compiler options, USE flags, and other build settings.

The emerge tool is central to Gentoo’s philosophy of high customizability and performance, emphasizing user control over system-building choices. It is distinct from other distributions’ package managers and has influenced similar tools in other projects.