quite possibly more a yum question than a centos question, but i'm a bit confused about the difference between listing "available" packages versus "updates" packages.

short example -- listing what the yum man page suggests should be "available" for installation, restricting myself to centosplus:

$ yum list available --disablerepo=* --enablerepo=centosplus ... snip ... Available Packages kernel-plus.x86_64 3.10.0-693.17.1.el7.centos.plus centosplus kernel-plus-abi-whitelists.noarch 3.10.0-693.17.1.el7.centos.plus centosplus kernel-plus-devel.x86_64 3.10.0-693.17.1.el7.centos.plus centosplus kernel-plus-doc.noarch 3.10.0-693.17.1.el7.centos.plus centosplus kernel-plus-headers.x86_64 3.10.0-693.17.1.el7.centos.plus centosplus kernel-plus-tools.x86_64 3.10.0-693.17.1.el7.centos.plus centosplus kernel-plus-tools-libs.x86_64 3.10.0-693.17.1.el7.centos.plus centosplus kernel-plus-tools-libs-devel.x86_64 3.10.0-693.17.1.el7.centos.plus centosplus perf.x86_64 3.10.0-693.17.1.el7.centos.plus centosplus postfix.x86_64 2:2.10.1-6.0.1.el7.centos centosplus postfix-perl-scripts.x86_64 2:2.10.1-6.0.1.el7.centos centosplus postfix-sysvinit.noarch 2:2.10.1-6.0.1.el7.centos centosplus python-perf.x86_64 3.10.0-693.17.1.el7.centos.plus centosplus $

first, i always thought "yum list available" would list only packages that i did not *already* have installed, and if i wanted to list installed packages eligible for update, i would run:

$ yum list updates --disablerepo=* --enablerepo=centosplus Updated Packages postfix.x86_64 2:2.10.1-6.0.1.el7.centos centosplus python-perf.x86_64 3.10.0-693.17.1.el7.centos.plus centosplus $

as you can see, the alleged updates are also listed as "available" from the first command -- has it always been this way? if so, i guess i just never noticed. (is there a way to list *only* available, uninstalled packages with some sort of filter?)

more curiously, some of the available packages from the centosplus repo have a package version that says merely "centos", not "centos.plus":

postfix.x86_64 2:2.10.1-6.0.1.el7.centos centosplus postfix-perl-scripts.x86_64 2:2.10.1-6.0.1.el7.centos centosplus postfix-sysvinit.noarch 2:2.10.1-6.0.1.el7.centos centosplus ^^^^^^

is that deliberate? it would seem to have the potential for confusion if one searches later for packages based on that string.

finally, the alleged update for python-perf:

python-perf.x86_64 3.10.0-693.17.1.el7.centos.plus centosplus

would seem to match *exactly* the currently installed numeric version on my system:

$ rpm -q python-perf python-perf-3.10.0-693.17.1.el7.x86_64 $

that is, both seem to be "3.10.0-693.17.1.el7", so how would this constitute an available "update"? perhaps there's something fundamental about version numbering and the centosplus repo i'm missing here.

rday