Can't locate [module_name].pm in @INC

Jram April 24, 2015

Troubleshooting guide for missing Perl modules in CentOS 7, making it more detailed and user-friendly.

The Problem: "Can't locate [module_name].pm in @INC"

When attempting to install or run a Linux daemon (a background process) on CentOS 7, you might encounter an error message like this:

Can't locate sys/syslog.pm in @INC

or

Can't locate Some/Other/Module.pm in @INC

What Does This Error Mean?

This error message tells you that a Perl script is trying to use a specific Perl module (a collection of reusable code), but that module is not installed on your system. Here's a breakdown:

  • [module_name].pm: This is the name of the missing Perl module. The .pm extension indicates it's a Perl module file.
  • @INC: This is a special Perl array that lists the directories where Perl looks for modules. When you run a Perl script, it searches these directories to find the modules it needs.
  • Can't locate... in @INC: This means the module file could not be found in any of the directories listed in @INC.

Why Does This Happen?

  • Missing Dependencies: The daemon you're installing might depend on certain Perl modules that are not installed by default on CentOS 7.
  • Outdated System: Your system might be missing required packages or repositories.
  • Manual Installation Issues: If you've previously attempted to install Perl modules manually, there might be conflicts or incorrect configurations.

The Solution: Install the Missing Perl Module Using yum

CentOS 7 uses the yum package manager to install software. The easiest way to resolve the missing module error is to use yum to install the corresponding Perl package.

Step-by-Step Instructions:

  1. Identify the Missing Module: Carefully read the error message to identify the exact name of the missing Perl module. In the example, it's sys/syslog.pm.

  2. Search for the Package Name: The Perl module filename (e.g., sys/syslog.pm) doesn't directly correspond to the package name that yum uses. You need to find the correct package name. A common convention is that the package name starts with perl- and then a portion of the module name. You can use yum search to find the package.

    Bash
    yum search perl-sys-syslog

    or if you don't know the full module name, try something more general.

    Bash
    yum search perl-sys
    • This command will search the available repositories for packages that contain the specified string.
    • Look for a package that seems to match the missing module.

  3. Install the Package: Once you've found the correct package name, use the yum install command to install it.

    Bash
    yum install -y perl-sys-syslog
    • Replace perl-sys-syslog with the actual package name you found.
    • The -y option automatically answers "yes" to any prompts, making the installation non-interactive.

  4. Verify the Installation: After the installation is complete, you can verify that the module is now available by running the original installation or daemon command again.

  5. Troubleshooting Tips:

    • Different Module Names: If your error message mentions a different module name (e.g., Some/Other/Module.pm), adapt the search and install commands accordingly.

    • Multiple Packages: Sometimes, a module might be included in multiple packages. Try searching for related packages if the first one doesn't work.

    • Enable EPEL Repository: If yum cannot find the package, you might need to enable the Extra Packages for Enterprise Linux (EPEL) repository. This repository contains many additional packages.

      Bash
      yum install -y epel-release

      Then, try searching and installing the package again.

    • Update Your System: Ensure your system is up-to-date.

      Bash
      yum update -y

    • Manual Installation (Advanced): If you still cannot find the package, you might need to install the module manually using cpan (Comprehensive Perl Archive Network). However, this is more advanced and should be used as a last resort.

Key Takeaways:

  • The "Can't locate... in @INC" error means a Perl module is missing.
  • Use yum search to find the correct package name.
  • Use yum install to install the package.
  • Enable the EPEL repository if necessary.
  • Keep your system up-to-date.

By following these steps, you should be able to resolve the missing Perl module error and continue with your daemon installation.

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Jram

Posted by Jram