REMOVE 32 bit PACKAGES FROM 64bit(CENTOS)

CentOS follows the upstream source in this respect, and the x86_64 installation by default will install ix86 32-bit packages on a 64-bit installation for compatibility purposes. Many server system administrators (and some desktop users) want a pure 64-bit system and so remove all 32-bit packages. This can be accomplished as follows:

yum remove \*.i\?86

To keep any 32-bit packages from being installed in future updates, edit your /etc/yum.conf and add the line:

exclude = *.i?86

Be aware that 32-bit applications, including some browser plugins that may only be available in 32-bit versions, will no longer work after this procedure.

You may also want to do this:

yum reinstall \*

The reason is that sometimes the /usr/share/ items (shared between BOTH packages) get removed when removing the 32-bit RPM packages.

RPM MANAGEMENT TIPS

REBUILD THE RPM FROM SRPM

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The pre-requisite packages required are ---

[user@linux ~]$yum groupinstall "Development Tools" 

[user@linux ~]$yum install yum-utils

OR

you can install only rpm-build.For CentOS most SRPMs targetted to be rebuilt on CentOS also need certain rpmbuild build macros and helper scripts, which are contained in package: redhat-rpm-config

[user@linux ~]$yum install redhat-rpm-config

[user@linux ~]$yum install rpm-build

The quickest way to rebuild the SRPM is to use the rpmbuild --rebuild command. This command will unpack the SRPM file into the specfile and the source files, and then it will build the RPM from the instructions on the specfile

[user@host ~]$ rpmbuild --rebuild /tmp/mypackage-1.0.0-1.src.rpm

If no error occurs, you can find mypackage-1.0.0-1.i386.rpm file under the ~/rpmbuild/RPMS/<architecture of your system> directory (for 64 bit it is x84_64 if 32 bit then it is i386). For more details read here

CHECK WHAT PACKET OWNS A PARTICULAR FILE

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[user@host~]$rpm -qf filename

[user@host~]$rpm -qf /usr/bin/crontab

cronie-1.4.4-7.el6.x86_64

CHECK WHAT CONFIGURATION FILE EXISTS FOR A PACKAGE

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[user@host~]$rpm -qc packagename

CHECK IF THE FILES INSTALLED BY A PACKAGE ARE STILL IN THE SAME STATE AS THEY WERE WHEN INSTALLED

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[user@host~]$rpm -qs packagename

This command will display all of the files installed by the package with a notation of "normal," "replaced," "not installed" and so on.