Author: djm

RancherOS on Raspberry Pi

The rancherOS is an operating system designed to run docker containers. It is actually designed as docker containers itself. Though they have a raspberry pi version and is does work, there are not that many docker images for a raspberry pi. The simple example of Linux-Dash used for testing your rancherOS on a RPi does not work for this reason. It can be made to work with a few changes. Create a DockerFile: FROM container4armhf/armhf-alpine LABEL architecture="ARMv7" RUN apk update && apk add unzip curl nodejs RUN curl -k -L -o RUN unzip WORKDIR linux-dash-master RUN...

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Changing the Linux command line prompt within a script

Sometimes the simplest things almost seems impossible. If you use long descriptive directory (folder) names and like to work at the terminal, it can quickly become a problem as you go deeper into the directory levels as the prompt displays the complete path from the home directory and becomes rather long. The command line prompt is set by PS1 and by default is (Linux Mint 18 XFCE): $ echo $PS1 \[\e]0;\u@\h \w\a\]${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\] \[\033[01;34m\]\w \$\[\033[00m\] The issue is that \w is used to display the complete path from home. A better option is to use \W as this will display...

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Docker on MS-Windows

Well, Docker on MS-Window is a chore! It’s all a bit of a hack, so here are some notes to help you along. Editing files in MS-Windows to run in Docker. Docker uses a Linux vm within Oracle’s Virtualbox. It is normally called ‘default’. Therefore the configuration files and the program files (python etc.) are actually read and run within Linux in this virtual machine. No, Docker is not virtualizing MS-Windows! There is an encoding difference between a Dos-based file and a Linux-based file. Dos-based files are ANSI with end-of-line markers of a CR+LF (carriage return or control-M –...

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Backup WP to AWS S3

Please note that this story is over 18 months old. It may be outdated.Backing up your WordPress web site can be a complicated process as there are many different parts that require backing up. You could just backup the whole Linux installation, but in itself produces a number of problems when restoring. It is easy to forget when developing a backup procedure that the reason of the backup is to restore it! And it should also be easy and practical. If you are using a EC2 server for your WordPress server, it is logical to back up to a...

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Old Kernels in AWS

Please note that this story is over 18 months old. It may be outdated.I have found that on the minimal virtual machine that you can have on AWS (includes the free setup) has a small /boot size and this can quickly become full as new kernels are installed, especially when they are automatically installed. When you run out of space, the install will fail, and this will confuse the ‘apt-get autoremove’ command so that old kernels cannot be removed (it also affects other installs/removals also). After a good hunt around, I found the best instructions to fix this problem...

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Pi Day

Please note that this story is over 18 months old. It may be outdated.Today is Pi Day due to today’s date – in american format – 3-14-15 or 3.1415(926 etc). and

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Pico TTS Engine on Raspberry PI

Please note that this story is over 18 months old. It may be outdated.The latest version of Rasbian OS for the Raspberry PI does not include the pico tts (text to speech) engine. Well, the data file available but the utils and lib files are missing. So, after some searching, I found a website in english, written by a german, who translated it from a french website, on how to download and compile the source. There is no date on the article, and the instructions are not that clear, so I have re-written them below: The source code is...

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Creating desktop launchers in Linux Mint Xfce

Please note that this story is over 18 months old. It may be outdated.There is a nice feature within Xcfe where you can create a program launcher on the desktop. You right-click on the desktop and select ‘Create Launcher’ from the displayed menu. In the name field, start typing the name of the application. A drop-down box will fill with possible options. In my case, I was adding a launcher for EtherApe: You may want to drag the right hand side out to clearly display the options in the drop-down display. I selected the EtherApe as root option and...

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Data Privacy Day

Please note that this story is over 18 months old. It may be outdated.Today is Data Privacy Day. This occurs every year on the 28 January. Data Privacy Day is an annual international celebration designed to promote awareness about privacy and education about best privacy practices. Click on the link above to go to the Data Privacy page for more information and a list of resources to aid you in keeping your data safe while...

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Open and Closed Programming Worlds.

Please note that this story is over 18 months old. It may be outdated.The perils of Vivek Haldar – his article ( covers the idea that a computer language or system can be a closed or open world. To some extent, this is true. For instance, JAVA can be considered a closed world, as it has it’s own tool set and virtual machine. Vivek uses Unix as the example of a open world, a loosely coupled system of programs and utilities which can be split apart and run on multiple systems; Unix being only one of many. The multivalued...

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What happened in 1986?

Please note that this story is over 18 months old. It may be outdated.I have been rather busy of late, doing a bit of reading and a lot of research regarding the NF² or The Nested Relational Model. While browsing my old Universities library last year, I discovered an old text-book on the subject of Object-Oriented Database Management by Kemper & Moerkotte. What is of real interest is that “Chapter 6 – Extensions of Relational DBMSs” has a rather good coverage of the “6.6 – The Nested Relational Model NF2” with a bunch of references or citations to papers...

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Document Paradigm in UniBasic

Please note that this story is over 18 months old. It may be outdated.Yet again, while running around the great inter-web, I found an interesting article which compares different database paradigms. The comparisons provided are between relational, document, key/value, and column-oriented databases. This lead me to thinking back to a comment that someone recently said to me that they use UniVerse as a document store database. At the time, I thought – what the … But then again, there just might be something in this: As I have stated before, I consider that the U2/PICK database model to be...

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