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Manage UPS Using Power Management on Ubuntu 16.04

UPS means Uninterruptible Power Supply. The UPS is a device which has a rechargeable battery provides electrical power for a few minutes after the outage, depending on its specifications. However, UPS is not a power generator and its mission is NOT to continue the operation of the computer for all the duration of the blackout.

Power Management module on Ubuntu 16.04 is a flexible tool to manage your computer UPS. If you have a UPS dedicated to your workstation, Ubuntu "Power Management" is all you need.


How To Setup Virtualbox on Ubuntu 16.04

Virtualbox is an advanced virtualization platform. It runs on Windows, Linux, Macintosh, and Solaris hosts and supports a large number of guest operating systems. It is available as Open Source Software (GPL2). It is lightweight and actively developed, so it is suitable for use in workstations.

I use Virtualbox to create virtual machines mainly for testing:

  • to test my current Operating System before applying major changes to running version
  • to test my software projects in a clone of a production (Debian) server
  • to test my software projects in Microsoft Windows workstations

This is a simple guide to setup Oracle Virtualbox on Ubuntu 16.04


How to Create Partition Image Backup and Restore Using Clonezilla

Clonezilla is a Free and Open Source bootable GNU/Linux distribution for disk or partition imaging and cloning. There are two versions available:

In this tutorial Clonezilla Live is used to create partition image and then restore it in a virtual machine (Virtualbox).


Easily Compress and/or Encrypt Files in Linux Using 7z (p7zip) Archiver

p7zip is a port of 7za.exe for POSIX systems like Unix (Linux, Solaris, OpenBSD, FreeBSD, Cygwin, AIX), MacOS X and also for BeOS and Amiga.

7z is an excellent archiving software offering high compression ratio and strong AES-256 encryption.


Fix Mouse Sensitivity in Ubuntu 16.04

After installation of Ubuntu Desktop 16.04, a nasty surprise awaits you. Mouse is very sensitive (practically unusable) in most systems with wireless mouse. Probably, this will not happen in systems with old wired mouse. Trying to fix mouse sensitivity, using System Settings → Mouse and Touchpad, you will see that it is not possible.

Fortunately, there is an easy way to fix it, using xset (user preference utility for X).


Package Management and System Update in Ubuntu Desktop

Ubuntu Desktop releases offer handy GUI utilities to handle Package Management and System Update:

  • Repository management: Software & Updates
  • Add - remove software:
    • Ubuntu Software Center (or simply “Software” in other Ubuntu flavors) or
    • Synaptic Package Manager (actually, an apt front-end). Please note that Synaptic is not included in default installation. To install it, open a terminal and use: sudo apt-get install synaptic
  • Software and System Update:

Using a desktop computer (workstation), it is more possible that you will use these GUI utilities. However, you can use the command line if you prefer. It's a matter of choice.

It is recommended to select a Long Term Support (LTS) Ubuntu Release for your Desktop Workstation, so you will have Updates for 5 years. A new LTS version is released every 2 years. Current LTS release (2016 Oct) is Ubuntu 16.04 (Xenial Xerus).


How to Remove Old Kernels in Debian and Ubuntu

After installing a new Linux kernel, old kernels are not automatically deleted. They remain in your disk (/boot partition). You have to delete them manually. Why?

The main reason is to save disk space, which occupied by old kernels. Some systems may become unusable if not enough disk space is available in /boot partition. However, disk space is not a problem in modern systems.

An other reason is to clean up Grub boot menu. In Ubuntu, Grub boot menu is hidden by default. You can display it by pressing "SHIFT" continuously at boot time. More details in this post.

You will never delete your current kernel, of course. It is recommended to keep at least one or two older kernels, so you can boot your system in an emergency situation (hardware or software compatibility issues with the current kernel).


How To Create Fast And Reliable Backup Using Rsnapshot

rsync is probably the most common solution for backup on Linux, because it is extremely fast and makes incremental backups (transfer "only differences" between two versions of a file), which is extremely useful in network backups.

However, synchronization (sync) a folder to a backup device, is far from being considered "backup", as it does not keep old versions of files. The problem is solved with rsync as described in the famous article Easy Automated Snapshot-Style Backups with Linux and Rsync, by Mike Rubel.


Update Postgres Major Version in Debian Jessie

Postgresql update is not a trivial task.

According to PostgreSQL Versioning policy:

A major release is numbered by increasing either the first or second part of the version number, e.g. 9.1 to 9.2.

Minor releases are numbered by increasing the third part of the version number, e.g. 9.2.3 to 9.2.4

Upgrading to a minor version is done through the upgrade process of Debian.

For major versions, the process is much more complex. This post describes the upgrading from 9.4 to 9.5 in a Debian (Jessie) server.


A Simple Guide to Obtain and Install an SSL Certificate

More and more companies use SSL certificates (small data files that digitally bind a cryptographic key) to protect their customers sensitive data, as username, password and credit card number, as they are transmitted over the internet.

There is a large number of companies provide SSL certificates (Certificate authorities) - see here - and a wide variety of SSL certificates. So, it is often difficult for the average user to choose the right SSL certificate.

In the following post I describe the process of obtaining and installing a Comodo PositiveSSL SSL certificate on a Debian server with Apache 2.4.10 over port 443 for domain "site.com" There are small differences in this procedure in other operating systems and web servers. You will usually find detailed documentation on the site where you purchased the SSL certificate.

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