Technology Tales

Adventures & experiences in contemporary technology

Welcome

  • Technology is pervasive these days and touches our lives in many ways we do not realise. Software matters as much as hardware, and there is more to the latter than consumer devices we use for computing, telephony, photography or videography. From all this, we should recognise that computer code is at work in many different places.

  • All the appraisals and how-tos that you find here come from the above. Devices may not feature that much but working with computer software does, and that even extends to its creation. In addition, system management and data computing inspire new posts on finding something worthwhile to share. The hope is that you encounter something interesting in whatever you find.

Stop Excel 365 saving files to OneDrive by default

8th June 2024

Recently, I was doing some work in Excel (while I use the 365 version, this may work with others too) when I found it offering to save a file to OneDrive by default. My preference is to keep everything local, especially given the limitations of online storage. Thus, I sought a way to do just this.

Stop Excel 365 saving files to OneDrive by default

That meant going to File > Options and then to the Save tab. In there, I found the option called Save to Computer by default and activated that. The default local location can be changed too, but I left this as it was because I tend to use multiple file locations anyway. Clicking on the OK button after making the change that I wanted was enough to set the behaviour as I required, and I no longer see the prompt for online storage since then.

Resolving “repository doesn’t support architecture i386” error when checking for updates to Brave Browser on Linux

7th June 2024

Recently, I started to observe the following message when doing my usual update routine on Linux Mint (Debian, Ubuntu and their variants are likely affected as well):

N: Skipping acquire of configured file 'main/binary-i386/Packages' as repository 'https://brave-browser-apt-release.s3.brave.com stable InRelease' doesn't support architecture 'i386'

As the message suggests, there was something amiss with the repository set up for Brave, a browser that I added for extra privacy. Since Firefox remains the main one that I use, Brave is something that I have in hand for when I need it. Handily, its installation routine adds in repository information for keeping it up to date. However, there is an issue with what you find in /etc/apt/sources.list.d/brave-browser-release.list. By default, the line appears like thus:

deb [signed-by=/usr/share/keyrings/brave-browser-archive-keyring.gpg] https://brave-browser-apt-release.s3.brave.com/ stable main

To avoid the i386 error, it needs to look like this instead:

deb [signed-by=/usr/share/keyrings/brave-browser-archive-keyring.gpg arch=amd64] https://brave-browser-apt-release.s3.brave.com/ stable main

The difference between the tow is the presence of arch=amd64 in the second version. This stops the search for non-existent i386 files, the 32 bit version in other words. With Y2K2038 in the offing, the days of 32 bit computing architectures are numbered because there is a real limit to the magnitude of the dates that can be represented in any case. Thus, sticking with 64 bit ones is both the present for many and the future for all.

Upgrading from OpenMediaVault 6.x to OpenMediaVault 7.x

29th May 2024

Having an older PC to upgrade, I decided to install OpenMediaVault on there a few years ago after adding in 6 TB and 4 TB hard drives for storage, a Gigabit network card to speed up backups and a new BeQuiet! power supply to make it quieter. It has been working smoothly since then, and the release of OpenMediaVault 7.x had me wondering how to move to it.

Usefully, I enabled an SSH service for remote logins and set up an account for anything that I needed to do. This includes upgrades, taking backups of what is on my NAS drives, and even shutting down the machine when I am done with what I need to do with it.

Using an SSH session, the first step was to switch to the administrator account and issue the following command to ensure that my OpenMediaVault 6.x installation was as up-to-date as it could be:

omv-update

Once that had completed what it needed to do, the next step was to do the upgrade itself with the following command:

omv-release-upgrade

With that complete, it was time to reboot the system, and I fired up the web administration interface and spotted a kernel update that I applied. Again, the system was restarted, and further updates were noticed and these were applied, again through the web interface. The whole thing is based on Debian 12.x, but I am not complaining as long as it quietly does exactly what I need of it. There was one slight glitch when doing an update after the changeover, and that was quickly sorted.

Later on, I ran into trouble because I had changed my broadband. Because the router address had changed, the system lost its access to the rest of the internet. The web interface also got disable and was issuing 502: Bad Gateway errors. The solution was to execute the following command with superuser privileges:

omv-salt stage run deploy

That took quite a while to run, though. After it completed, I needed to work out what the administrator credentials were. With that done, I could log in and update the network details as needed to restore external internet access. Since then, all has been well.

Updating fail2ban filters for WordPress

18th April 2024

Not so long ago, WordPress warned me that some of its Fail2ban filters were obsolete because I have the corresponding WP-fail2ban plugin installed, and the software is present on the underlying Ubuntu Server system. The solution was to connect to the server by SSH and execute the following commands.

wget https://plugins.svn.wordpress.org/wp-fail2ban/trunk/filters.d/wordpress-hard.conf
wget https://plugins.svn.wordpress.org/wp-fail2ban/trunk/filters.d/wordpress-soft.conf
wget https://plugins.svn.wordpress.org/wp-fail2ban/trunk/filters.d/wordpress-extra.conf
sudo mv wordpress-*.conf /etc/fail2ban/filter.d/

The first three commands download the updated configuration files before the last moves them to their final location. It is tempting to download the files directly to that final location, only for WGET to create new files instead of overwriting the old ones as required.

Catching keyboard interruptions in a Python script for a more orderly exit

17th April 2024

A while back, I was using a Python script to watch a folder and process photos in there, whenever a new one was added. Eventually, I ended up with a few of these because I was unable to work out a way to get multiple folders watched in the same script.

In each of them, though, I needed a tidy way to exit a running script in place of the stream of consciousness that often emerges when you do such things to it. Because I knew what was happening anyway, I needed a script to terminate quietly and set to uncover a way to achieve this.

What came up was something like the code that you see below. While I naturally did some customisations, I kept the essential construct to capture keyboard interruption shortcuts, like the use of CTRL + C in a Linux command line interface.

if __name__ == '__main__':
    try:
        main()
    except KeyboardInterrupt:
        print('Interrupted')
        try:
            sys.exit(130)
        except SystemExit:
            os._exit(130)

What is happening above is that the interruption operation is captured in a nested TRY/EXCEPT block. The outer block catches the interruption, while the inner one runs through different ways of performing the script termination. For the first termination function call, you need to call the SYS package and the second needs the OS one, so you need to declare these at the start of your script.

Of the two, SYS.EXIT is preferable because it invokes clean-up activities while OS._EXIT does not, which might explain the “_” prefix in the second of these. In fact, calling SYS.EXIT is not that different to issuing RAISE SYSTEMEXIT instead because that lies underneath it. Here OS._EXIT is the fallback for when SYS.EXIT fails, and it is not all that desirable given the abrupt action that it invokes.

The exit code of 130 is fed to both, since that is what is issued when you terminate a running instance of an application on Linux anyway. Using 0 could negate any means of picking up what has happened if you have downstream processing. In my use case, everything was standalone, so that did not matter so much.

Automating writing using R and Claude

16th April 2024

Automation of writing using AI has become prominent recently, especially since GPT came to everyone’s notice. It is more than automation of proofreading but of producing the content itself, as Mark Hinkle and Luke Matthews can testify. Figuring out how to use Generative AI needs more than one line prompts, so knowing what multi-line ones will work is what is earning six digit annual salaries for some.

Recently, I gave this a go when writing a post that used content from a Reddit post thread. The first step was to extract the content from the thread, and I found that I could use R to do this. That meant installing the RedditExtractoR package using the following command:

install.packages("RedditExtractoR")

Then, I created a short script containing the following lines of code with placeholders added in place of the actual locations:

library("RedditExtractoR")

write.csv(get_thread_content("<URL for Reddit post thread>"), "<location of text file>")

The first line above calls the RedditExtractoR package for use so that its get_thread_content function could be used to scape the thread’s textual content. This was then fed to write.csv for writing out a text file with content.

Once I had the text file, I could upload it to Anthropic’s Claude for the next steps. Firstly, I got it to give me a summary of the thread discussion before I asked it to give me the suggested solutions to the issue. Impressively, it capably provided me with the latter.

Now armed with these answers, I set to crafting the post from them. Claude did not do all the work for me, but it certainly helped with the writing. This is something that I fancy exploring further, especially given how business computing is likely to proceed in the next few years.

Getting rid of the “Get more security upgrades through Ubuntu Pro with ‘esm-apps’ enabled” message when performing a system update

15th April 2024

Not so long ago, I got the above message while running sudo apt upgrade on an Ubuntu Server system. This was not the first time that this kind of thing happened to me, so I started searching the web for a solution. You do get to see complaints about advertising, but these are never useful.

Accordingly, here are some possible ways of remediating the situation:

  • Execute the following commands to disable the responsible services, renaming the configuration file to prevent it from being used (deleting or editing the configuration file to remove the unwanted content are other options):

    sudo systemctl mask apt-news.service

    sudo systemctl mask esm-cache.service

    sudo mv /etc/apt/apt.conf.d/20apt-esm-hook.conf
    /etc/apt/apt.conf.d/20apt-esm-hook.conf.disabled

  • Alternatively, simply remove the ubuntu-advantage-tools package, which contains the /etc/apt/apt.conf.d/20apt-esm-hook.conf file.
  • Another option is to remove the ubuntu-pro-client package.
  • Lastly, there also is the possibility of enabling ESM, though that was not desirable for me.

In my case, it may have been the penultimate option on the list that I chose. In any case, I was rid of the unwanted message.

Dealing with the following message issued when using Certbot on Apache: “Unable to find corresponding HTTP vhost; Unable to create one as intended addresses conflict; Current configuration does not support automated redirection”

12th April 2024

When doing something with Certbot on another website not so long ago, I encountered the above message when executing the following command (semicolons have been added to separate the lines):

sudo certbot --apache

The solution was to open /etc/apache2/sites-available/000-default.conf using nano and update the ServerName field (or the line containing this keyword) so it matched the address used for setting up Let’s Encrypt SSL certificates. The mention of Apache in the above does make the solution specific to this web server software, so you will need another solution if you meet this kind of problem when using Nginx or another web server.

Using a BASH command to count the files in a directory

12th March 2024

As part of my backup workflow, I maintain a machine running OpenMediaVault that I only power up when backups are to be performed. Typically, this often happens when I have new photography images to load, and I have a NAS that acts as an online backup system. The OpenMediaVault machine is a near-offline counterpart to the NAS for added safety.

Recently, I needed to check on the number of image files in a directory from an SSH session because of a need to create a new repository for 2024. Some files from this year had ended up in the 2023 one, and I needed to be sure that nothing from last year ended in the 2024 folder, or vice versa. Getting a file count from a trusted source was a quick way of doing exactly this.

Due to clumsiness with the NAS, I had to do this using the OpenMediaVault machine. While I could go mounting drives on an interim basis, it was quicker to work from a BASH session. The trick was to use the wc command for counting the lines output by an invocation of the ls command. An example follows:

ls -l | wc -l

The -l (as in l for Lima) switch forces wc to count lines, while the counterpart (same letter) for ls forces it to list the contents in long form, one item per line. Thus, counting the number of lines gets you the count of the number of files. The call to the ls command can be customised to add other things life the number of dot files, but the above was enough for my purposes. When the files in both 2023 directories matched, I was satisfied that all was in order.

AttributeError: module ‘PIL’ has no attribute ‘Image’

11th March 2024

One of my websites has an online photo gallery. This has been a long-term activity that has taken several forms over the years. Once HTML and JavaScript based, it then was powered by Perl before PHP and MySQL came along to take things from there.

While that remains how it works, the publishing side of things has used its own selection of mechanisms over the same time span. Perl and XML were the backbone until Python and Markdown took over. There was a time when ImageMagick and GraphicsMagick handled image processing, but Python now does that as well.

That was when the error message gracing the title of this post came to my notice. Everything was working well when executed in Spyder, but the message appears when I tried running things using Python on the command line. PIL is the abbreviated name for the Python 3 pillow package; there was one called PIL in the Python 2 days.

For me, pillow loads, resizes and creates new images, which is handy for adding borders and copyright/source information to each image as well as creating thumbnails. All this happens in memory and that makes everything go quickly, much faster than disk-based tools like ImageMagick and GraphicsMagick.

Of course, nothing is going to happen if the package cannot be loaded, and that is what the error message is about. Linux is what I mainly use, so that is the context for this scenario. What I was doing was something like the following in the Python script:

import PIL

Then, I referred to PIL.Image when I needed it, and this could not be found when the script was run from the command line (BASH). The solution was to add something like the following:

from PIL import Image

That sorted it, and I must have run into trouble with PIL.ImageFilter too, since I now load it in the same manner. In both cases, I could just refer to Image or ImageFilter as I required and without the dot syntax. However, you need to make sure that there is no clash with anything in another loaded Python package when doing this.

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