Apparently, when doing "yum update", and it fails miserably, you can end up with duplicate versions of packages in the RPM database. This seems harmless, but is annoying. yum provides a tool to check for this, but I was not able to find anything that would automatically repair it. So here's a little tip:

$ yum check duplicates | awk '/is a duplicate/ {print $6}' > /tmp/DUPES
$ yum remove `cat /tmp/DUPES`

 Of course, before you remove the dupes, make sure to examine the tmp file (/tmp/DUPES) and make sure it looks ok.

Update:

There seems to be a command to do this, package-cleanup has an option for it. E.g.

$ package-cleanup --cleandupes

However, testing this command on a second box having the same problem gave bad results, it seems to have uninstalled the "real" packages too.

A while ago, I wrote about installing System Tap on my Fedora box, which requires some debuginfo packages. I mumbled something about what yum commands to use, here. As it turns out, this is a common enough task to do that there's a special Python Yum application for it, debuginfo-install. For example:

# debuginfo-install gcc.i386 glibc.i686

Neat!

My Fedora Core 7 box recently ended up in some state where my perl installation was seriously messed up. I'd get errors about mismatch in platform architecture, problems with sockets etc. etc. So, I really wanted to have yum reinstall all my perl packages. I couldn't find a way to do that, but I managed to achieve something similar using various commands. Here are the steps I followed:

# rpm -qa --qf '%{NAME}\n' | grep '^perl-' > /tmp/perl.pkgs
# rpm -e --justdb --nodeps perl `cat /tmp/perl.pkgs`
# mv /usr/lib/perl5 /usr/lib/perl5-
# yum install perl `cat /tmp/perl.pkgs`

PLEASE! Be careful with these commands, make sure you know what you're doing, check the /tmp/perl.pkgs file to make sure it seems reasonable etc. Once this is all done and finished, I removed the old perl5 library (perl5-).

As an alternative, you could also do something like

# rpm -q --qf '%{NAME}\n' --whatrequires perl > /tmp/perl.pkgs

but that will reinstall more packages than absolutely necessary, I think.

I wanted to get SystemTap to run on my Fedora Core 6 box, and had problems getting it running. The README says to install the kernel-debuginfo, which I had problems getting going. It turns out I was just being stupid, and didn't run yum properly. All I really had to do was:

% sudo yum install systemtap
% sudo yum --enablerepo=core-debuginfo --enablerepo=updates-debuginfo  install kernel-debuginfo

More information about System Tap is available here.

I use yum on pretty much a daily basis, and I've added a small collection of repos (repository). I use livna and FreshRPMs for instance. Now, for some reason these two repositories overlap, meaning, if I run yum update, livna will try to upgrade my freshrpm packages. Up until now, I've managed around this by using --enablerepo and --disablerepo. However, there's a much better way, I installed a yum plugin called yum-priorities.

Using yum (obviously), I simply installed this on my Fedora Core box with

# yum install yum-priorities

With this plugin installed, all I have to do is to give the FreshRPMs repo a higher priority (lower priority value) than the livna repo (default priority is 99). For example:

[freshrpms]
name=Fedora Core $releasever - $basearch - Freshrpms
priority=80
.
.
.

Now when I run yum update I get a message like

...
Loading "priorities" plugin
Setting up Update Process
Setting up repositories
Loading mirror speeds from cached hostfile
Reading repository metadata in from local files
0 packages excluded due to repository protections
96 packages excluded due to repository priority protections
No Packages marked for Update/Obsoletion

On my system at home, I run the latest Fedora development packages, which has both pros and cons. For instance, I'm pretty always up to date with all the tools I use, all automatically. However, it can be a pain sometimes to get yum to update properly, and a few times major breakage happens :-).

A while ago, I realized that there's a package availabe, called yum-utils, which provides quite a few useful tools, in particular, there's now a new repoquery tool. This can be used similar to the old rpm --fedoraprovides syntax, as well as many other uses. For instance

root@thor 426/0 # repoquery --whatprovides python
python-0:2.4.2-2.i386
root@thor 427/0 # repoquery --whatrequires python
plone-0:2.1.1-1.fc5.i386
mach-0:0.4.8-1.fc5.i386
system-config-lvm-0:1.0.8-1.0.noarch
rhn-applet-0:2.1.17-4.i386
plone-0:2.0.5-3.noarch
.
.
.

To install yum-utils (if not already installed, and you have yum properly configured for the development repo), all you do is

root@thor 428/0 # yum install yum-utils

Oh, and while I remember it, the old rpmdb-fedora DB package shouldn't be needed any more, I simply uninstalled it with

root@thor 329/0 # rpm -e rpmdb-fedora

I try to keep my system up to date using the Fedora "devel" packages, using the yum updater. Sometimes I would get errors like

unsigned package //var/cache/yum/development/packages/glibc-2.3.4-3.i686.rpm
unsigned package //var/cache/yum/development/packages/eog-2.8.1-1.i386.rpm
unsigned package //var/cache/yum/development/packages/pango-1.8.0-1.i386.rpm

The problem here is that not all development packages are signed, for whatever reason. Assuming you still trust Fedora, simply modify your yum configuration file (/etc/yum.repos.d/fedora-devel.repo in my case) to add a line like

gpgcheck=0