Gentoo Development Guide

ekeyword -- Keywording

The ekeyword tool should be used to manipulate the KEYWORDS variable. Using this tool will guarantee that you get the correct keyword ordering — manual editing may screw this up. The usage is ekeyword changes ebuilds. Valid changes are in the form sparc (to mark stable), ~sparc (to mark unstable), -sparc (to mark unavailable) and ^sparc (to remove the sparc keyword). The special all keyword is useful when doing version bumps — ekeyword ~all foo-1.23.ebuild will drop all currently present keywords to unstable. See ekeyword-1 for details.