CentOS – find packages provided by repositories

CentOS, how-to

A quick note to myself… This is what I do when I need to find which packages are provided by a certain repository. First I update the list of the available packages:

# yum check-update

Then I do a listing of them (bold is mine):

# yum repolist
Loaded plugins: fastestmirror, security
Loading mirror speeds from cached hostfile
* base: mirrors.prometeus.net
* epel: fr2.rpmfind.net
* extras: mirrors.prometeus.net
* updates: mirrors.prometeus.net
Excluding Packages from CentOS-5 - Base
Finished
Excluding Packages from CentOS-5 - Updates
Finished
repo id repo name status
base CentOS-5 - Base 3,612+29
epel Extra Packages for Enterprise Linux 5 - x86_64 7,241
extras CentOS-5 - Extras 266
updates CentOS-5 - Updates 95
repolist: 11,214

At this point, if I need to find what packages are provided by the EPEL repository and write that list on a file, I’ll simply digit:

# rpm -qa | grep epel > epel-list.txt

how-to fix the XS version of Scalar::Util error in CentOS / RHEL / Fedora

CentOS, Fedora, FLOSS, Red Hat

It’s being some month now that at work we have encountered a nasty problem with Perl’s module Compress::Zib usage in a tool developed by a colleague. At the moment to start the graphical rendering of a web page the system gave error to our users.

Searching in Apache2’s log I’ve encoutered many error of this kind:

dualvar is only available with the XS version of Scalar::Util at /var/www/html/$MY-APP-PATH/perl/Compress/Zlib.pm line 8

This is because the Scalar-List-Utils module precompiled in RHEL/Fedora/CentOS and similar does NOT have the support of XS weaken function.

You will see a lot of bugs issued on this topic in this part of Linux distro’s.

My solution was to install perl-Task-Weaken package:

In fact as we can read in the package’s description:

rpm -qi perl-Task-Weaken
...
URL         : http://search.cpan.org/dist/Task-Weaken/
Summary     : Ensure that a platform has weaken support
Description : One recurring problem in modules that use Scalar::Util's weaken function is that it is not present in the pure-perl variant.

This restores the functionality testing to a dependency you do once in your Makefile.PL, rather than something you have to write extra tests for each time you write a module.

Happy coding!

Error booting Fedora in VirtualBox

CentOS, Fedora

I am in the middle of the work for a GNU/Linux keynote & hands-on demo for some colleagues.

Since I’m a loyal Fedora/CentOS user I’m installing the latest Fedora 15 on my MacBook’s VirtualBox.

Fedora screenshots

Everything went ok during the installation until first reboot on which the system told me:

FATAL: INT18: BOOT FAILURE"

remaining into the error mode and forcing me to manually reboot.

If this happens to you too be sure to check if the installation media (the cd-rom or the dvd-rom) is still present in the player (!!!) and remove it.

It happears to be a know issue with VirtualBox, since a bug #2680 was opened 3 years ago and still unresolved (probably because it’s unclear if it’s VirtualBox or Fedora dvd boot system fault).
Ejecting the optical media solved my issue, cheers!
😉

how to install RMySQL on CentOS

CentOS

A quick note for who have the need of installing RMySQL on CentOS (or RHEL).

On my system R is installed via the EPEL repository (as I’ve added in the comments of this post of this very blog).

Given this I went to the RMySQL project page and downloaded both the RMySQL_0.7-5.tar.gz and the (required) DBI_0.2-5.tar.gz packages.

This because installing the R-DBI package provided by the activated repository on my system gave me errors during the actual RMySQL installation.

So, as root – since the installation was needed system-wide – i gave those two following commands:

[root@testing ~]# R CMD INSTALL DBI_0.2-5.tar.gz
[root@testing ~]# R CMD INSTALL RMySQL_0.7-5.tar.gz

Then all the user needed to do was loading into his R environment the new modules!
Happy coding!


For future reference:

  • CRAN – RMySQL package
  • CRAN – DBI package