Some notes I kept when I was learning how to use yum.

Installing a package that has been excluded

The file /etc/yum.conf may contain an 'excludes' line that will disallow updates of any of packages listed. To bypass this, you can comment out those packages in /etc/yum.conf, or you can one-off it like this:

yum --disableexcludes all install gcc

Finding which repo has the file you need

yum provides '*apxs*'

You may need to add '--disableexcludes all' too.

Listing the files in a package

repoquery --list apache

Using a specific repo

yum --disablerepo='*' --enablerepo='reponame' list available