How do I update a package on Gentoo Linux

Question

How do I update a package in Gentoo Linux?

Answer 1

This is what you need to read, an intro to portage, the package manager in Gentoo.

To update everything (including dependencies and changes to use flags), then

emerge -avDuN world

To update a single package (again paying attention to dependencies etc):

emerge -avDuN <package-name>

A basic update, without checking for dependency updates would be

emerge -avu <package-name>

The -a means "ask" which is for confirmation, and the -v means "verbose", to give more info about what it is doing.