Draft of usual commands required in the #centos irc channel

You may have been directed to this page because you have called for help on a CentOS irc channel. This is a set of commands that are usually required in order to resolve your issue. Please use http://pastebin.centos.org to publish the results and post just the pastebin URL it provides in the channel.

1. Before you ask

Please don't ask things like: Can nobody help?

We recommend that you read How To Ask Questions The Smart Way.

2. IRC Topic

Read it! as of 2012/03/08

12:30 Topic for #centos: Welcome to #centos | Current: 6.2, 5.8 |  
Don't paste in here, use http://pastebin.centos.org/ | http://wiki.centos.org/irc | 
Backports: │http://tinyurl.com/r77l2 | Some thinking required | 
Be polite and considerate | 
CentOS-4 is past its End of Life : http://lists.centos.org/pipermail/centos-announce/2012-February/018462.html

see also: spoon-feeding

3. Kernel Version and CentOS Release

$ uname -a
$ rpm -q centos-release

from some servers may truly be not CentOS:

Check your yum config files:

$ rpm -V yum centos-release ; ls /etc/yum.repos.d/ ; yum repolist; grep -ir exclude  /etc/yum.*

4. Multiarch packages

To see the specific architecture (usually 32 bits compatibility libraries) of packages on a machine:

rpm -qa --qf "%{name}-%{version}-%{release}.%{arch}\n" | sort ; \
  rpm -q --qf "%{name}-%{version}-%{release}.%{arch}\n" glibc\*

5. CPAN and source compiles related

Installing perl modules by CPAN is NOT SUPPORTED, use the 3rd parties repositories to install perl modules.

$ which perl; rpm -q perl; rpm -V perl

Example of a missing perl module message and a yum command line to search for it:

Can't locate LWP/UserAgent.pm in @INC
...
$ yum provides "perl(LWP::UserAgent)"
perl-libwww-perl.noarch : A Perl interface to the World-Wide Web
# yum install perl-libwww-perl

This is because CPAN ignores the packaging system, and will overwrite existing CentOS files, some of which are core to making perl work properly.

In a broader sense, replacing some core system library, such as 'zlib', with binaries from a version compiled from sources, bypasses the protections of SOname checking for incompatibility, which RPM provides. The result after doing so is something, but it is certainly no longer CentOS.

6. Additional Resources

...you should also take a look at the following resources, FAQs and hints:

technical resources

7. Common Errors

irc centos request (last edited 2012-04-04 23:12:33 by AlanBartlett)