APT Listing Packages – Ubuntu / Debian

Do you ever wonder how many thousands of packages are installed on your Linux system? Even a fairly modest Linux system is likely to have well over a thousand packages installed. And there are many ways to get details on what they are. Here are some of the most useful commands for gaining insights into the packages installed on your Linux system using APT on Ubuntu / Debian systems.

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Software RAID Recovery Tutorial

This tutorial will walk through the troubleshooting and recovery of a failed disk on a Software RAID setup. Especially mirroring the boot partition which is important when replacing disk and making sure the OS boots up properly after replacement.  This tutorial was done on Ubuntu 14.04 but should still work on other distributions such as RHEL and CentOS.

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Redirect HTTP to HTTPS on Apache

SSL secured websites or HTTPS has now become a must to have on website, especially those handling sensitive client information. Having a HTTPS enabled website means that a intruder can’t intrude to communication between users and website. HTTPS not only secures communication but is now a requirement for many new features like http2, which requires you to have https enabled on your server. Having a HTTPS enabled website also improves your Google SEO (Search Engine Optimization) ranking.

In this tutorial, we will discuss two methods on how we can redirect http traffic to https on Apache web servers.
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USB Ports and Versions Explained

Universal Serial Bus, more commonly known as the USB has been around for quite some time now with almost every device following the standard. From our I/O devices to storage drives and even mobile phones can be connected using the USB standard. USB ports version will be explained below

This standard has evolved over the years from its inception in the mid 90’s and has had multiple versions through its history.

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Setup Master Slave replication in MariaDB

Databases are arguably one of the main component of any modern application. And one of the most popular implementation of SQL databases is Mysql or the new replacement MariaDB. As a system administrator, you probably have installed and configured a database before. This tutorial will walk though setting up the master-slave replication of MariaDB.
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How to remove unused kernel images from CentOS/RHEL systems

Every time you update your CentOS Linux and the update includes a new kernel image update the system will not remove your old kernel but it will cumulatively add new kernel to the top of your Linux kernel installed list. Normally, this does not present any issue to your running system and you are not required to take any action to remove any old and unused kernel images.

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Recover disk usage after deleting large file in Linux

Disks getting full on Linux is a common scenario any administrator have probably experienced. There are usually some large files in /var/log directory that can be compressed or deleted to save disk space. Have you ever experienced deleting a large log file and noticed that the disk usage remained the same ? It’s as if the file size usage is not released even though you’ve deleted it?

This scenario can happen if you deleted/renamed/moved an existing file that is currently in use by a running program. This usually happens on log files that are not rotated regularly and then when the file size becomes large, you deleted (or compressed) the file without even checking if it is in-use. Don’t worry, you can still recover your disk space as shown from the example below.

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