List All Packages Installed by a Specific Repo in CentOS / RedHat with YUM

Red Hat Enterprise Linux (RHEL), Fedora, CentOS and Scientific Linux allows administrators to add and enable multiple repositories (repos) to install software packages that are not included in the default base and updates repositories. Over time, the [...]

CentOS YUM / RPM Error: rpmts_HdrFromFdno / rpmdbNextIterator: Header V3 RSA/SHA1 Signature Key ID BAD

When running YUM or RPM commands, the following errors occurred: error: rpmts_HdrFromFdno: Header V3 RSA/SHA1 Signature, key ID XXXXXXXX: BAD error: rpmdbNextIterator: skipping h# XXXX Header V3 RSA/SHA1 Signature, key ID XXXXXXXX BAD Error: Cannot retrieve metalink [...]

By |2016-12-09T08:39:11+00:00December 9th, 2016|Categories: Linux|Tags: , , |17 Comments

Cannot Retrieve Metalink for Repository: EPEL

When using yum to install or update software packages through "yum install" or "yum update" commands, the following stop error occurred: Loaded plugins: fastestmirror, security Loading mirror speeds from cached hostfile Error: Cannot retrieve metalink for repository: [...]

Create & Migrate Existing Working RedHat / CentOS System to RAID 1 / RAID 10

Linux system has built-in support for software RAID, through MD devices aka Linux Software RAID. Most Linux distributions such as Red Hat Enterprise Linux (RHEL) and CentOS allows you to easily set up RAID arrays while installing [...]

By |2016-12-09T08:39:11+00:00December 9th, 2016|Categories: Linux|Tags: , , , , , |7 Comments

Sync RHEL / CentOS Server Time with Authoritative Time Server Automatically

In Linux server running Red Hat Enterprise Linux (RHEL) or CentOS, the time of the server may become incorrect and differ from official real clock after some time due to clock drift, as not all clocks is [...]

By |2016-12-09T08:39:15+00:00December 9th, 2016|Categories: Linux|Tags: , , , , |0 Comments

Mail: Command Not Found in Linux (RedHat / CentOS / Debian / Ubuntu)

In Linux operating system such as Red Hat Enterprise Linux (RHEL), CentOS and Ubuntu, the following error may occur mail when running mail command to access a mailbox, maildir, mail file: -bash: mail: command not found The [...]

By |2016-12-09T08:39:15+00:00December 9th, 2016|Categories: Linux|Tags: , , , , , , , |0 Comments

Perl Module This Distribution Requires a Working Compiler at Makefile.PL

When compiling and installing a Perl module from source via CPAN or CPANM (CPANMinus) on Linux such as RHEL, CentOS and Ubuntu, a compiling error may occur when running the Makefile. The error message shown can vary, [...]

By |2016-12-09T08:39:16+00:00December 9th, 2016|Categories: Linux|Tags: , , , , , , , , , , |0 Comments

Perl Modules Need Module::Build But Is Not Installed

In Webmin, when attempting to install Perl modules, some modules may fail to install from packages. In such cases, the system will automatically try to install from source. However, when trying to build and install modules, Webmin [...]

By |2016-12-09T08:39:16+00:00December 9th, 2016|Categories: Linux|Tags: , , , , , |0 Comments

How to Read User Mail in the Webmin / Virtualmin / Cloudmin

Webmin is a web-based GUI interface to manage UNIX and Linux systems. Webmin is also the base of which Virtualmin, the web hosting control panel like Plesk or Cpanel, and Cloudmin, which is used to manage virtual [...]