yum install --downloadonly --downloaddir=/tmp/hoge/ hoge
yum install --downloadonly --downloaddir=/tmp/hoge/ --disablerepo=updates hoge
yum --nogpgcheck --disablerepo=* update *.rpm
yum --nogpgcheck --disablerepo=* localinstall *.rpm
yum clean all
rm -rf /var/cache/yum/
RHEL 8.x 系は
yum clean all
rm -rf /var/cache/dnf/