Ebuild
└─ `emerge` commands

The following are emerge commands often used while preparing an ebuild.

Install build dependencies for a package:

emerge -o <atom>

Install build dependencies and test dependencies for a package:

emerge -o --with-test-deps=y <atom>

Install build dependencies for a package, ignoring the binary package:

emerge -o --usepkg-exclude=<atom> <atom> 

Install build dependencies for a package with the doc USE flag enabled:

emerge -o <atom>[doc]

Clean redundant packages:

emerge --depclean

Clean redundant packages and all build dependencies:

emerge --depclean --with-bdeps=n