Memory Matrix

When I first obtained a CompTIA A+ certification some time ago, the concept of bit rot related to what happens to software reliability as the number of updates to the system increases. Over time, software that worked in years past ceases to work as new system updates block system calls or change permissions and files that the software originally relied upon. This slow decaying of reliability was called bit rot. There are some other definitions floating around on the internet, but that is the one most relevant for me.

To prevent this and reduce the amount of time spent in sorting out the bit rot introduced to my investments by Microsoft’s proclivities, I have standardized on two operating systems for major time investments in computing that occupy my life.  Windows still has a place since I sometimes use Windows only games to play with my child.  Other than that necessity, I have built the things I rely on for use with Linux.  The two versions that I have standardized on are Debian and Fedora. Specifically Debian 12 and Fedora 38.  These are not what is used for the website, but they are the major components of my anti-bitrot infrastructure.  I am aware this may not be good security practice, but this isn’t to get me a job, this is to serve an aging man and his family reliably over time.

There are a few reasons that I selected Fedora 38 and Debian 12. Fedora 38 still has Python 2.7 in the repositories.  It was within 2 versions for upgrading from Fedora 36. Fedora 36 was what I was running in my Windows Subsystem for Linux instance, and I upgraded it to Fedora 38.   When deciding to move back to bare metal for my Linux software development and automation needs, I decided to standardize on that one.  Debian has a 32 bit version. I have both the 32-bit and 64-bit deployed in my network.  Debian 32 bit allows on to easily 32-bit builds of Java on a Linux server.  One can add the testing repository and have the latest Java in 32 bit form.  32-bit Java is necessary to run older Minecraft versions.  My family has a large set of mod-collections and old Java Minecraft instances and maps going back about 8 years. I can then run the latest JVM and the latest Minecraft on the same server because the 32bit JVM is available.  It is very annoying to try and  manage 32bit and 64bit Java virtual machines on the same host, so having it all 32-bit solves a huge problem.  One can add the Debian 11 repository and install Python2.7 if one wants to use old Python versions.  I need this old Python version for a project that I worked on over the course of the last 8 years.

The general anti-bit rot measure for Debian is to always use apt-get to install packages as this will leave the .deb file in the cache.  Then copy those .deb files on a regular basis to another location for use as a repository for other Debian installations.  This can be configured to work via a cron job.  Debian is really the only long-term viable game in town if one wants a 32-bit anti-bitrot bunker that will last into the future, over say, a ten year time horizon. Save the .deb files on a private web-server inside the network and periodically update that repository with the files copied via the sweeps from the cache directory.

For Fedora, this should work with any version.  Fedora 38 is the one I use.  Edit the /etc/dnf/dnf.conf file to say keep_cache=True, and this will save the dowloaded RPMS.  One can then build their repository using only what they need if so desired.  The other genuine long term standardization option is to mirror the entire repositories to the private webserver within one’s network.  To do this, install yumdownloader.   Then, move all of the .repo files from /etc/yum.repos.d except for one to a temporary location.  Then, go into a directory with a lot of space.  For Fedora 38, the complete mirror was 229GB.  Then use yumdownloader * and it will download all files from that repository.  Then, use yumdownloader –source * and it will download all source packages for the packages that it just downloaded.  Then, go back to /etc/yum.repos.d and switch that .repo file out with one that was moved previously, and repeat the process until all repositories have been completely downloaded.  Then, copy all downloaded RPMS to one large directory on the webserver and use createrepo to create the meta data.  Then on the client machines, create a .repo pointing to your own webserver, and move the existing .repo files in /etc/yum.repos.d to an archival location.   Then all of your installations will occur from your own webserver and all machines will have the same versions of packages.

In my case, I then install the data science specifics that I need for the automated software that I created.  The process varies slightly depending on whether the system is Fedora or Debian.

For Debian:

Add bullseye to sources.list
Install python2 via bullseye repositories
Install pip via the downloaded file from https://linuxhint.com/install-pip-on-debian-11/ that is to say,
1. wget https://bootstrap.pypa.io/pip/2.7/get-pip.py
2. python2 ./get-pip.py
Apt-get install libcurl4-openssl-dev

R:
Install.packages(‘curl’)
Install.packages(‘fpp2’)
Install.packages(‘magrittr’)
Install.packages(‘urca’)
Install.packages(‘vars’)
Install.packages(‘psych’)
Apt-get install r-cran-rjava
Install.packages(‘rJava’)
Install.packages(‘xlsx’)
Install.packages(‘Hmisc’)
Install.packages(‘prophet’)
Install.packages(‘dplyr’)
pip2 install parsedatetime==2.5
apt-get install awscli
pip2 install boto3
apt-get install r-cran-car

Troubleshooting steps if .xlsx and others are not built:
Are all R packages installed successfully with a 0 exit status?

On Fedora, the repositories do not contain R components in the same way the Debian repositories do.  Here is the process for Fedora 38.

Used the script https://bootstrap.pypa.io/pip/2.7/get-pip.py
pip2 install parsedatetime==2.5 –user
dnf install libcurl
dnf install libcurl-devel
dnf install R
dnf install awscli
pip2 install boto3 –user
dnf install cmake

Within R:
install.packages(‘car’)
install.packages(‘curl’)
install.packages(‘fpp2′)
install.packages(‘magrittr’)
install.packages(‘urca’)
install.packages(‘vars’)
install.packages(‘psych’)
install.packages(‘rJava’)
install.packages(‘xlsx’)
install.packages(‘Hmisc’)
install.packages(‘prophet’)
install.packages(‘dplyr’)

Use about:config –> browser.uidensity .

browser.uidensity is set to 0 by default.  Changer the  value to 1 and it takes immediate effect.

Chromium:

Joplin Web Clipper, Zotero Connector, floccus bookmarks sync, uBlock Origin, Quick Javascript Switcher, SingleFile, uMatrix

Firefox:

floccus bookmarks sync, Joplin Web Clipper, Search by Image, uMatrix, Undo Close Tab, Zotero, uBlock Origin

[x]  Removed some Firefox/LibreWolf extensions

[+] Added Zotero and uBlock Origin, which have been long used, but neglected with regards to appearing in this list.

To add a new virtual disk and move the existing Linux partition to the new disk use the following process. The process assumes standard partitions without the use of Logical Volume Manager (LVM).

1. Backup the existing VM. One good way to do that is to clone the Virtual Machine and use the procedure on the new Virtual Machine.

2. Create the partition and format it.

$ mount /dev/sbd /mnt

$ shopt -s dotglob

$ rsync -aulvXpogtr /var/* /mnt

$ nano /etc/fstab

Add this line, replacing sdb and ext4 as necessary:

/dev/sdb /var ext4 defaults,noatime,nofail 0 2

Then

$ mv /var/ /var.old

Reboot and enjoy the new drive.

Use printenv to see what environment variables are set.

#!/usr/bin/env bash
printenv
    set -x

The .bashrc file I use on CentOS6

# .bashrc

# User specific aliases and functions

alias rm='rm -i'
alias cp='cp -i'
alias mv='mv -i'

# Source global definitions
if [ -f /etc/bashrc ]; then
        . /etc/bashrc
fi

# system variables
export VISUAL=nano  # sets nano as the crontab editor
export GZIP=-9      # maximum compression
export XZ_OPT=-9    # maximum compressions

# ls modifications
alias ll='ls -alF'
alias la='ls -A'
alias l='ls -CF'

# calculator
calc() { echo "$*" | bc -l; }

# Generate a UUID
uuid() { UUID=$(cat /proc/sys/kernel/random/uuid) && echo $UUID; }

# CHANGE SHELL/WINDOW TITLE
# Works on Opensuse 15.3
# PS1=$PS1"\[\e]0;test1\a\]"
shellrename() { read -p "Enter new shell name: " name && PS1=$PS1"\[\e]0;${name}\a\]"; }

# For older versions of gnome-terminal
# shellrename() { read -p "Enter new shell name: " name && PROMPT_COMMAND='echo -ne "\033]0;${name}\007"'; }

# Zen Burn
# Another old way that works great in gnome-terminal while causing problems
# in some configurations involving SSH:
echo -ne '\e]12;#BFBFBF\a'
echo -ne '\e]10;#DCDCCC\a'
echo -ne '\e]11;#3F3F3F\a'
echo -ne '\e]4;0;#3F3F3F\a'
echo -ne '\e]4;1;#705050\a'
echo -ne '\e]4;2;#60B48A\a'
echo -ne '\e]4;3;#DFAF8F\a'
echo -ne '\e]4;4;#506070\a'
echo -ne '\e]4;5;#DC8CC3\a'
echo -ne '\e]4;6;#8CD0D3\a'
echo -ne '\e]4;7;#DCDCCC\a'
echo -ne '\e]4;8;#709080\a'
echo -ne '\e]4;9;#DCA3A3\a'
echo -ne '\e]4;10;#C3BF9F\a'
echo -ne '\e]4;11;#F0DFAF\a'
echo -ne '\e]4;12;#94BFF3\a'
echo -ne '\e]4;13;#EC93D3\a'

dnf install oracle-epel-release-el9
dnf install iftop

iptraf is already in the default repositories.

Some useful aliases that are not always preconfigured on every Linux version:

alias ll=’ls -alF’
alias la=’ls -A’
alias l=’ls –CF’

To eliminate the DRM warning in Firefox and Librewolf without enable DRM, add this to “userChrome.css”:

 notification[value="drmContentDisabled"]{ display:none !important; }

toolkit.legacyUserProfileCustomizations.stylesheets must be set to true in about config.

Here is a script that checks to ensure the database is running and restarts the service if it is not running.  This was used on a very low memory server to ensure a database remained operational, despite it sometimes crashing due to out of memory errors.

#!/bin/bash

timestamp="$(date)"
systemctl stop httpd && echo "${timestamp}" Stopping Apache... >> /home/centos/administration/apache.log
systemctl is-active mariadb && echo "${timestamp}" MariaDB is active so not starting >> /home/centos/administration/mariadb_active.log || echo "${timestamp}" MariaDB is not Active >> /home/centos/administration/mariadb_inactive.log
systemctl is-active mariadb && echo "${timestamp}" No need to restart MariaDB || systemctl start mariadb
systemctl start httpd && echo "${timestamp}" restarting apache...>> /home/centos/administration/apache.log

Revisions: 21 January 2024, first publication

The Thunderbird developers are moving to a new user interface code base for Thunderbird 115 and Thunderbird 102 is the last version that will work with the historical userChrome.css customizations. The userbase for Mozilla products has continually shrunk over the past few years and the chances of equivalent customization abilities being discovered and written about strike me as pretty low.  Because of the change, I have mirrored Thunderbird 102.14 for Windows and Linux in 64-bit and 32-bit versions in the event that the old versions disappear from the Mozilla site. The Source is available on the Mozilla mirror as of August 11, 2023.  The releases are located here.

The userChrome.css below allows the following persistent tag colors.  It also contains text customization for the interface.  And it contains alternate row highlighting, where one row is light grey and the other white.  The alternate row highlighting conflicts with the background colors for tags.  One must choose which feature to have. The userChrome.css goes in the profile directory in a subfolder called chrome.

The code for highlighting the tag backgrounds was found on a French website located here. E.g. C:\Users\username\AppData\Roaming\Thunderbird\Profiles\1a2b3cde.default-release\chrome

@namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul");
/* set default namespace to XUL */
/* thanks to Jean-Claude, */
/* https://forums.mozfr.org/viewtopic.php?t=143173 */
/*Important tag IMPORTANT*/ 
treechildren::-moz-tree-row(T_24label1)
{
      border-bottom: 1px solid #FFFFFF !important;
      background-color:  #FF0033   !important;
}
treechildren::-moz-tree-cell-text(T_24label1)
{
      color: #FFFFFF !important;
}
treechildren::-moz-tree-row(T_24label1, selected)
{
      background-color: #b71c1c !important;
}
treechildren::-moz-tree-cell-text(T_24label1, selected)
{
  color: #00FF00  !important;
}

/*Travail tag   WORK*/
treechildren::-moz-tree-row(T_24label2)
{
  border-bottom: 1px solid #FFFFFF !important;
  background-color:  #FF9900   !important;
}
treechildren::-moz-tree-cell-text(T_24label2)
{
  color: #FFFFFF !important;
}
treechildren::-moz-tree-row(T_24label2, selected)
{
  background-color: #FF9900 !important;
}
treechildren::-moz-tree-cell-text(T_24label2, selected)
{
  color: #00FF00  !important;
}

/*Personnel tag PERSONAL*/ 
treechildren::-moz-tree-row(T_24label3)
{
  border-bottom: 1px solid #FFFFFF !important;
  background-color:  #009900   !important;
}
treechildren::-moz-tree-cell-text(T_24label3)
{
  color: #FFFFFF !important;
}
treechildren::-moz-tree-row(T_24label3, selected)
{
  background-color: #009900 !important;
}
treechildren::-moz-tree-cell-text(T_24label3, selected)
{
  color: #00FF00  !important;
}

/*A faire tag*/
treechildren::-moz-tree-row(T_24label4)
{
  border-bottom: 1px solid #FFFFFF !important;
  background-color:  #3333FF   !important;
}
treechildren::-moz-tree-cell-text(T_24label4)
{
  color: #FFFFFF !important;
}
treechildren::-moz-tree-row(T_24label4, selected)
{
  background-color: #3333FF !important;
}
treechildren::-moz-tree-cell-text(T_24label4, selected)
{
  color: #00FF00  !important;
}

/*Peut attendre tag*/
treechildren::-moz-tree-row(T_24label5)
{
  border-bottom: 1px solid #FFFFFF !important;
  background-color:  #993399  !important;
}
treechildren::-moz-tree-cell-text(T_24label5)
{
  color: #FFFFFF !important;
}
treechildren::-moz-tree-row(T_24label5, selected)
{
  background-color: #993399 !important;
}
treechildren::-moz-tree-cell-text(T_24label5, selected)
{
  color: #00FF00  !important;
}

/*test tag*/
treechildren::-moz-tree-row(Ttest)
{
  border-bottom: 1px solid #FFFFFF !important;
  background-color:  #FFCC33  !important;
}
treechildren::-moz-tree-cell-text(Ttest)
{
  color: #FFFFFF !important;
}
treechildren::-moz-tree-row(Ttest, selected)
{
  background-color: #FFCC33 !important;
}
treechildren::-moz-tree-cell-text(Ttest, selected)
{
  color: #00FF00  !important;
}

/* 9 August 2023 Additions */
/* Set Font Size In Folder Pane */

#folderTree >treechildren::-moz-tree-cell-text {
  /*font-family: Lucida Sans !important;*/
  font-size: 9pt !important; }

/* Set Font Size In Thread Pane */

#threadTree >treechildren::-moz-tree-cell-text {
  /*font-family: Lucida Sans !important;*/
  font-size: 9pt !important; }

#threadTree treechildren::-moz-tree-row    {
/*  border-bottom: 1px dotted grey !important;  */
  height: 24px !important; }

/* folder list spacing */

#folderTree treechildren::-moz-tree-row    {
  height: 24px !important; }

/* The silver background color on alternating rows */
#threadTree treechildren::-moz-tree-row(odd) {
  -moz-appearance: none !important;
  background-image: none !important;
  /* the !important property overrides previous styling rules */
  /* this line enables alternate color row highlighting, but
  tag backgrounds on this row cannot be highlighted.  Only one 
  background highlighting can be applied Disabled 9 August 2023
  to enable tag background highlights*/
  /* background-color:#F3F6FA !important; */

}

#threadTree treechildren::-moz-tree-row(selected) {
  background-color: -moz-Dialog !important;
}
#threadTree treechildren::-moz-tree-row(selected, focus) {
  background-color: Highlight !important;
}

#folderTree treechildren::-moz-tree-row(selected) {
  -moz-appearance: none !important;
  background-image: none !important;
  background-color: Highlight !important;
}
#folderTree treechildren::-moz-tree-row(selected, focus) {
  -moz-appearance: none !important;
  background-image: none !important;
  background-color: Highlight !important;
}