CentOS - Jan 2015 - how to delete a trashed kernel

I have a screwed up disk arrangement, but I have had no trouble because of it
after using it over a year. Recently I did a yum update. After starting the
update, which included a new kernel, it seemed to either freeze or loop. It was
a long time at the? prompt and I got impatient and did a Ctrl C. I then tried to
re-boot. The result was a kernel panic. I am keeping 5 kernels and when I
select? the second kernel it boots OK. Now I would like to remove the bad
kernel. One other thing that I don't understand and may be relevant, the
name of the bad package is??????? kernel-2.6.32-504.3.3.el6.centos-plus.i386
 I have never noticed a "centos-plus" in a kernel name before. Does
the centos-plus repo deal out kernels?I have tried yum remove and "gpk
application" (add and remove software) with no luck.I have tried google,
but all the solutions for kernel deletions were to delete old kernels. I
don't want to do that because I would be deleting my backups.?I am in no
hurry because I can still boot and it is possible that if I can wait through
several kernel updates yum might delete the bad one after an update.?I should
have mentioned that I am using grub2 to boot, although I don't think that
has anything to do with deleting the kernel package.I would appreciate any
advice (except "go back to windows")

On Jan 1, 2015, at 3:49 PM, Don Vogt <dnvot at yahoo.com> wrote:
> when I select  the second kernel it boots OK. Now I would like to remove
the bad kernel.
The only thing that makes this tricky is that you can?t just say ?rpm -e kernel?
because there is more than one ?kernel? package installed.  You need to know the
exact package name.

It sounds like you know the full package name, but if you didn?t, a command like
this will find it for you:

    $ rpm -qf /boot/vmlinuz-3.10.0-123.4.2.el7.x86_64

vmlinuz-* is the kernel image on most Linuxes, and they usually live in /boot.

The command to remove that particular kernel on an EL7 box is:

    $ sudo rpm -e kernel-3.10.0-123.4.2.el7.x86_64

I?m assuming you?re using EL7 and you told it you wanted your user to be a
trusted admin during install.  Otherwise, you might need to su up to root to do
this.  Alas, sudo is not universal:

    http://unix.stackexchange.com/questions/48522/how-universal-is-sudo
> I have never noticed a "centos-plus" in a kernel name before.
Does the centos-plus repo deal out kernels?
Clearly, the answer is ?yes?.

This happened because you enabled the centosplus repo in /etc/yum.repos.d, then
said ?yum update?.  Whenever the centosplus kernel is newer, it gets installed
as the default instead of the stock OS kernel.

This is why I never leave nonstandard repos permanently enabled.  I always
enable them on a one-off basis:

    $ sudo yum --enablerepo=centosplus some-weird-package-i-need

That enables the centosplus repo for just that one command.
> I would appreciate any advice (except "go back to windows?)
You asked for it: Get and read some good books on Linux.

I would recommend both some books that focus generally on Unix type systems
(e.g. Unix System Administration Handbook) as well as some focused specifically
at the version of Linux you are using right now.

One gets you practical details you can use today, while the other gets you
philosophy that will inform your reaction to the changes that will come
throughout the rest of your career.

You cannot properly learn Linux just by Googling and asking questions on forums,
mailing lists, and Unix.SE.  Books are still the densest form of reliable
technical information available.