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silver imac on top of brown wooden table

New blog layout

The blog has a new layout. Some of the most important changes:

  • Much smaller logo. The logo was taking up waaaaay too much space.
  • The thumbnails have a shadow on the main page.
  • I hope that the font is easier to read. I might tweak this later.
  • Less clutter in the sidebar!
  • The social links have moved to the Contact page.
  • The top menu is rearranged a bit.
  • The blog archive displays the full article, not just an excerpt.
  • Infinite scroll! I don’t know yet if I like it, I might change it later.
  • The blog archive has 2 columns. Again, I’m not sure about this, might change it later. Feedback is welcome, leave a comment!
  • The most recent post is displayed full width.
  • On individual posts the thumbnail image is now the background of the title.
  • I’m still not entirely happy that the author is shown at the bottom of each blog post. I’m the only author here, so that’s useless, but I have not yet found how to remove that. EDIT: fixed with some extra CSS. Thanks for the tip, Frank!

Do you have any suggestions or comments on the new layout?

Unboxing the Ghent box (video in Dutch)

Last month I moved from Merelbeke to Ghent. I registered my new address on the government website, and last week I was invited to update my eID with my new address.

I made an appointment with one of the administrative centers of the city. The entire process took less than 5 minutes, and at the end I got a welcome gift: a box with a lot of information about the city services.

It’s been a while since I last did an unboxing video. The audio is in Dutch, maybe if I’m not too lazy (and only if people ask for it in the comments) I’ll provide subtitles.

Unboxing van het verwelkomingspakket van @StadGentVideos
Pocket knife with eleven blades, Chinese copy of t (pocket knives)

Convert ODT to PDF with Pandoc and LaTeX

  • Receive an ODT file (OpenDocument Text Document).
  • Everyone: opens the file with either LibreOffice or even Microsoft Office nowadays, apparently.
  • Me: uses Pandoc and LaTeX to convert the file to PDF and read it in Evince because I don’t have LibreOffice installed and I’m too lazy to upload the document to Google Docs.

I needed to review an addendum to a rental contract. (I moved! I’ll write about that later.) The addendum was sent to me in ODT format. At the time, my desktop pc was still packed in a box. On my laptop (a 2011 MacBook Air with Ubuntu 20.04) I only have the most essential software installed, which for me doesn’t include an office suite. I could install LibreOffice, but why make it easy if I can also do it the hard way? 😀

I do have Evince installed, which is a lightweight PDF viewer. To convert ODT to PDF I’m using Pandoc, which is a Swiss army knife for converting document formats. For PDF it needs the help of LaTeX, a document preparation system for typesetting.

First I installed the required software:

$ sudo apt install pandoc texlive texlive-latex-extra
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following additional packages will be installed:
  libapache-pom-java libcommons-logging-java libcommons-parent-java libfontbox-java libpdfbox-java preview-latex-style texlive-base texlive-binaries
  texlive-fonts-recommended texlive-latex-base texlive-latex-recommended texlive-pictures texlive-plain-generic tipa
Suggested packages:
  libavalon-framework-java libcommons-logging-java-doc libexcalibur-logkit-java liblog4j1.2-java texlive-xetex texlive-luatex pandoc-citeproc
  context wkhtmltopdf librsvg2-bin groff ghc php python r-base-core libjs-mathjax node-katex perl-tk xzdec texlive-fonts-recommended-doc
  texlive-latex-base-doc python3-pygments icc-profiles libfile-which-perl libspreadsheet-parseexcel-perl texlive-latex-extra-doc
  texlive-latex-recommended-doc texlive-pstricks dot2tex prerex ruby-tcltk | libtcltk-ruby texlive-pictures-doc vprerex
The following NEW packages will be installed:
  libapache-pom-java libcommons-logging-java libcommons-parent-java libfontbox-java libpdfbox-java pandoc preview-latex-style texlive texlive-base
  texlive-binaries texlive-fonts-recommended texlive-latex-base texlive-latex-extra texlive-latex-recommended texlive-pictures texlive-plain-generic
  tipa
0 upgraded, 17 newly installed, 0 to remove and 1 not upgraded.
Need to get 116 MB of archives.
After this operation, 448 MB of additional disk space will be used.
Do you want to continue? [Y/n]

Just to compare, installing LibreOffice Writer would actually use less disk space. Pandoc is a lot faster though.

$ sudo apt install libreoffice-writer
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following additional packages will be installed:
  libabw-0.1-1 libboost-date-time1.71.0 libboost-filesystem1.71.0 libboost-iostreams1.71.0 libboost-locale1.71.0 libclucene-contribs1v5
  libclucene-core1v5 libcmis-0.5-5v5 libe-book-0.1-1 libeot0 libepubgen-0.1-1 libetonyek-0.1-1 libexttextcat-2.0-0 libexttextcat-data libgpgmepp6
  libjuh-java libjurt-java liblangtag-common liblangtag1 libmhash2 libmwaw-0.3-3 libmythes-1.2-0 libneon27-gnutls libodfgen-0.1-1 liborcus-0.15-0
  libraptor2-0 librasqal3 librdf0 libreoffice-base-core libreoffice-common libreoffice-core libreoffice-math libreoffice-style-colibre
  libreoffice-style-tango librevenge-0.0-0 libridl-java libuno-cppu3 libuno-cppuhelpergcc3-3 libuno-purpenvhelpergcc3-3 libuno-sal3
  libuno-salhelpergcc3-3 libunoloader-java libwpd-0.10-10 libwpg-0.3-3 libwps-0.4-4 libxmlsec1 libxmlsec1-nss libyajl2 python3-uno uno-libs-private
  ure
Suggested packages:
  raptor2-utils rasqal-utils librdf-storage-postgresql librdf-storage-mysql librdf-storage-sqlite librdf-storage-virtuoso redland-utils
  libreoffice-base gstreamer1.0-plugins-bad tango-icon-theme fonts-crosextra-caladea fonts-crosextra-carlito libreoffice-java-common
The following NEW packages will be installed:
  libabw-0.1-1 libboost-date-time1.71.0 libboost-filesystem1.71.0 libboost-iostreams1.71.0 libboost-locale1.71.0 libclucene-contribs1v5
  libclucene-core1v5 libcmis-0.5-5v5 libe-book-0.1-1 libeot0 libepubgen-0.1-1 libetonyek-0.1-1 libexttextcat-2.0-0 libexttextcat-data libgpgmepp6
  libjuh-java libjurt-java liblangtag-common liblangtag1 libmhash2 libmwaw-0.3-3 libmythes-1.2-0 libneon27-gnutls libodfgen-0.1-1 liborcus-0.15-0
  libraptor2-0 librasqal3 librdf0 libreoffice-base-core libreoffice-common libreoffice-core libreoffice-math libreoffice-style-colibre
  libreoffice-style-tango libreoffice-writer librevenge-0.0-0 libridl-java libuno-cppu3 libuno-cppuhelpergcc3-3 libuno-purpenvhelpergcc3-3
  libuno-sal3 libuno-salhelpergcc3-3 libunoloader-java libwpd-0.10-10 libwpg-0.3-3 libwps-0.4-4 libxmlsec1 libxmlsec1-nss libyajl2 python3-uno
  uno-libs-private ure
0 upgraded, 52 newly installed, 0 to remove and 1 not upgraded.
Need to get 78,5 MB of archives.
After this operation, 283 MB of additional disk space will be used.
Do you want to continue? [Y/n] n
Abort.

Next, converting the file. It’s possible to tell Pandoc which file formats to use with the -f (from) and -t (to) switches, but it can usually guess correctly based on the file extensions.

$ time pandoc 2022-06-house-contract-adendum.odt -o 2022-06-house-contract-adendum.pdf

real	0m0,519s
user	0m0,475s
sys	0m0,059s

It took only half a second to convert the file. Opening LibreOffice takes a bit more time on this old laptop.

You can see the PDF document properties with pdfinfo:

$ pdfinfo 2022-06-house-contract-adendum.pdf 
Title:          
Subject:        
Keywords:       
Author:         
Creator:        LaTeX with hyperref
Producer:       pdfTeX-1.40.20
CreationDate:   Sat Jun 11 23:32:30 2022 CEST
ModDate:        Sat Jun 11 23:32:30 2022 CEST
Tagged:         no
UserProperties: no
Suspects:       no
Form:           none
JavaScript:     no
Pages:          2
Encrypted:      no
Page size:      612 x 792 pts (letter)
Page rot:       0
File size:      64904 bytes
Optimized:      no
PDF version:    1.5

I don’t want it in letter format, I want A4:

$ time pandoc -V papersize:a4 -o 2022-06-house-contract-adendum.pdf 2022-06-house-contract-adendum.odt

real	0m0,520s
user	0m0,469s
sys	0m0,060s
$ pdfinfo 2022-06-house-contract-adendum.pdf 
Title:          
Subject:        
Keywords:       
Author:         
Creator:        LaTeX with hyperref
Producer:       pdfTeX-1.40.20
CreationDate:   Sat Jun 11 23:40:16 2022 CEST
ModDate:        Sat Jun 11 23:40:16 2022 CEST
Tagged:         no
UserProperties: no
Suspects:       no
Form:           none
JavaScript:     no
Pages:          2
Encrypted:      no
Page size:      595.276 x 841.89 pts (A4)
Page rot:       0
File size:      64935 bytes
Optimized:      no
PDF version:    1.5

Then I could open the file with evince 2022-06-house-contract-adendum.pdf.

And yes, I know that addendum is with double d. 🙂

silver and black hard disk drive

Suspending cloud backup of a NAS that cannot be reached

I use CrashPlan for cloud backups. In 2018 they stopped their Home solution, so I switched to their Business plan.

It works very well on Linux, Windows and Mac, but it was always a bit fickle on my QNAP NAS. There is a qpkg package for CrashPlan, and there are lots of posts on the QNAP support forum. After 2018, none of the solutions to run a backup on the NAS itself stopped working. So I gave up, and I didn’t have a backup for almost 4 years.

Now that I have mounted most of the network shares on my local filesystem, I can just run the backup on my pc. I made 3 different backup sets, one for each of the shares. There’s only one thing that I had to fix: if Crashplan runs when the shares aren’t mounted, then it thinks that the directories are empty, and it will delete the backup on the cloud storage. As soon as the shares come back online, the files are backed up again. It doesn’t have to upload all files again, because Crashplan doesn’t purge the files on it’s cloud immediately, but the file verification still happens. That takes time and bandwidth.

I contacted CrashPlan support about this issue, and this was their reply:

I do not believe that this scenario can be avoided with this product – at least not in conjunction with your desired setup. If a location within CrashPlan’s file selection is detached from the host machine, then the program will need to rescan the selection. This is in inherent drawback to including network drives within your file selection. Your drives need to retain a stable connection in order to avoid the necessity of the software to run a new scan when it sees the drives attached to the device (so long as they’re within the file selection) detach and reattach.

Since the drive detaching will send a hardware event from the OS to CrashPlan, CrashPlan will see that that hardware event lies within its file selection – due to the fact that you mapped your network drives into a location which you’ve configured CrashPlan to watch. A hardware event pointing out that a drive within the /home/amedee/Multimedia/ file path has changed its connection status will trigger a scan. CrashPlan will not shut down upon receiving a drive detachment or attachment hardware event. The program needs to know what (if anything) is still there, and is designed firmly to track those types of changes, not to give up and stop monitoring the locations within its file selection.

There’s no way around this, aside from ensuring that you either keep a stable connection. This is an unavoidable negative consequence of mapping a network drive to a location which you’ve included in CrashPlan’s file selection. The only solution would be for you to engineer your network so as not to interrupt the connection.

Nathaniel, Technical Support Agent, Code42

I thought as much already. No problem, Nathaniel! I found a workaround: a shell script that checks if a certain marker file on the network share exists, and if it doesn’t, then the script stops the CrashPlan service, which will prevent CrashPlan from scanning the file selection. As soon as the file becomes available again, then the CrashPlan service is started. This workaround works, and is good enough for me. It may not be the cleanest solution but I’m happy with it.

I first considered using inotifywait, which listens to filesystem events like modifying or deleting files, or unmount. However when the network connection just drops for any reason, then inotifywait doesn’t get an event. So I have to resort to checking if a file exists.

#!/bin/bash
file_list="/home/amedee/bin/file_list.txt"

all_files_exist () {
    while read -r line; do
        [ -f "$line" ]
        status=$?
        if ! (exit $status); then
            echo "$line not found!"
            return $status
        fi
    done < "$file_list"
}

start_crashplan () {
    /etc/init.d/code42 start
}

stop_crashplan () {
    /etc/init.d/code42 stop
}

while true; do
    if all_files_exist; then
        start_crashplan
    else
        stop_crashplan
    fi
    sleep 60
done
  • file_list.txt contains a list of testfiles on different shares that I want to check. They all have to be present, if even only one of them is missing or can’t be reached, then the service must be stopped.
/home/amedee/Downloads/.testfile
/home/amedee/Multimedia/.testfile
/home/amedee/backup/.testfile
  • I can add or remove shares without needing to modify the script, I only need to edit file_list.txt – even while the script is still running.
  • Starting (or stopping) the service if it is already started (or stopped) is very much ok. The actual startup script itself takes care of checking if it has already started (or stopped).
  • This script needs to be run at startup as root, so I call it from cron (sudo crontab -u root -e):
@reboot /home/amedee/bin/test_cifs_shares.sh

This is what CrashPlan support replied when I told them about my workaround:

Hello Amedee,

That is excellent to hear that you have devised a solution which fits your needs!

This might not come in time to help smooth out your experience with your particular setup, but I can mark this ticket with a feature request tag. These tags help give a resource to our Product team to gauge customer interest in various features or improvements. While there is no way to use features within the program itself to properly address the scenario in which you unfortunately find yourself, as an avenue for adjustments to how the software currently operates in regards to the attachment or detachment of network drives, it’s an entirely valid request for changes in the future.

Nathaniel, Technical Support Agent, Code42

That’s very nice of you, Nathaniel! Thank you very much!

silver and black hard disk drive

Mounting NAS shares without slow startup

I have a NAS, a QNAP TS-419P II. It’s about a decade old and it has always served me well. Due to various reasons I have never used it in an efficient way, it was always like a huge external drive, not really integrated in the rest of my filesystems.

The NAS has a couple of CIFS shares with very obvious names:

  • backup
  • Download
  • Multimedia, with directories Music, Photos and Videos

(There are a few more shares, but they aren’t relevant now.)

In Ubuntu, a user home directory has these default directories:

  • Downloads
  • Music
  • Pictures
  • Videos

I want to store the files in these directories on my NAS.

Mounting shares, the obvious way

First I moved all existing files from ~/Downloads, ~/Music, ~/Pictures, ~/Videos to the corresponding directories on the NAS, to get empty directories. Then I made a few changes to the directories:

$ mkdir backup
$ mkdir Multimedia
$ rmdir Music
$ ln -s Multimedia/Music Music
$ rmdir Pictures
$ ln -s Multimedia/Photos Pictures
$ rmdir Videos
$ ln -s Multimedia/Videos Videos

The symbolic links now point to directories that don’t (yet) exist, so they appear broken – for now.

The next step is to mount the network shares to their corresponding directories.

The hostname of my NAS is minerva, after the Roman goddess of wisdom. To avoid using IP addresses, I added it’s IP address to /etc/hosts:

127.0.0.1	localhost
192.168.1.1     modem
192.168.1.63	minerva

The shares are password protected, and I don’t want to type the password each time I use the shares. So the login goes into a file /home/amedee/.smb:

username=amedee
password=NOT_GOING_TO_TELL_YOU_:-p

Even though I am the only user of this computer, it’s best practice to protect that file so I do

$ chmod 400 /home/amedee/.smb

Then I added these entries to /etc/fstab:

//minerva/download	/home/amedee/Downloads	cifs	uid=1000,gid=1000,credentials=/home/amedee/.smb,iocharset=utf8 0 0
//minerva/backup	/home/amedee/backup	cifs	uid=0,gid=1000,credentials=/home/amedee/.smb,iocharset=utf8 0 0
//minerva/multimedia	/home/amedee/Multimedia	cifs	uid=0,gid=1000,credentials=/home/amedee/.smb,iocharset=utf8 0 0
  • CIFS shares don’t have a concept of user per file, so the entire share is shown as owned by the same user. uid=1000 and gid=1000 are the user ID and group ID of the user amedee, so that all files appear to be owned by me when I do ls -l.
  • The credentials option points to the file with the username and password.
  • The default character encoding for mounts is iso8859-1, for legacy reasons. I may have files with funky characters, so iocharset=utf8 takes care of that.

Then I did sudo mount -a and yay, the files on the NAS appear as if they were on the local hard disk!

Fixing a slow startup

This all worked very well, until I did a reboot. It took a really, really long time to get to the login screen. I did lots of troubleshooting, which was really boring, so I’ll skip to the conclusion: the network mounts were slowing things down, and if I manually mount them after login, then there’s no problem.

It turns out that systemd provides a way to automount filesystems on demand. So they are only mounted when the operating system tries to access them. That sounds exactly like what I need.

To achieve this, I only needed to add noauto,x-systemd.automount to the mount options. I also added x-systemd.device-timeout=10, which means that systemd waits for 10 seconds, and then gives up if it’s unable to mount the share.

From now on I’ll never not use noauto,x-systemd.automount for network shares!

While researching this, I found some documentation that claims you don’t need noauto if you have x-systemd.automount in your mount options. Yours truly has tried it with and without noauto, and I can confirm, from first hand experience, that you definitely need noauto. Without it, there is still the long waiting time at login.

sky sunny wave space

Jag lär mig svenska 🇸🇪

Jag brukade skriva på den här bloggen på nederländska. Nu är det mest på engelska, men undantagsvis är det här blogginlägget på svenska.

I september 2020 började jag lära mig svenska på kvällsskolan i Aalst. Varför? Det finns flera anledningar:

  • Jag spelar nyckelharpa, ett typiskt svenskt musikinstrument. Jag gÃ¥r pÃ¥ kurser hemma och utomlands, ofta frÃ¥n svenska lärare. Det var sÃ¥ jag lärde känna människor i Sverige och dÃ¥ är det bra att prata lite svenska för att hÃ¥lla kontakten online.
  • När man slÃ¥r upp nÃ¥got pÃ¥ nätet om nyckelharpa är det ofta pÃ¥ svenska. Jag har ocksÃ¥ en underbar bok “Nyckelharpan – Ett unikt svenskt kulturarv” av Esbjörn Hogmark och jag vill kunna läsa den och inte bara titta pÃ¥ bilderna.
  • Jag tycker att Sverige är ett vackert land som jag kanske vill besöka nÃ¥gon gÃ¥ng. Norge ocksÃ¥, och där talar man en märklig dialekt av svenska. 😛
  • Jag vill gÃ¥ en kurs pÃ¥ Eric Sahlström Institutet i Tobo nÃ¥gon gÃ¥ng. DÃ¥ skulle det vara bra att förstÃ¥ lärarna pÃ¥ deras eget sprÃ¥k.
  • Jag gillar sprÃ¥k och sprÃ¥kinlärning! Det hÃ¥ller min hjärna fräsch och frisk. 😀

And if you didn’t understand anything: there’s always Google Translate!

green and grey circuit board

I have a ridiculous amount of kernels

In previous blogposts I wrote about how I found a possible bug in the Linux kernel, or more precisely, in the kernel that Ubuntu derived from the mainline kernel.

To be able to install any kernel version 5.15.7 or higher, I also had to install libssl3.

The result is that I now have 37 kernels installed, taking up little over 2 GiB disk space:

$ (cd /boot ; ls -hgo initrd.img-* ; ls /boot/initrd.img-* | wc -l)
-rw-r--r-- 1 39M mrt  9 09:54 initrd.img-5.13.0-051300-generic
-rw-r--r-- 1 40M mrt  9 09:58 initrd.img-5.13.0-19-generic
-rw-r--r-- 1 40M mrt  9 09:58 initrd.img-5.13.0-20-generic
-rw-r--r-- 1 40M mrt  9 09:57 initrd.img-5.13.0-21-generic
-rw-r--r-- 1 44M mrt 30 17:46 initrd.img-5.13.0-22-generic
-rw-r--r-- 1 40M mrt  9 09:56 initrd.img-5.13.0-23-generic
-rw-r--r-- 1 40M mrt  9 09:56 initrd.img-5.13.0-25-generic
-rw-r--r-- 1 40M mrt  9 09:56 initrd.img-5.13.0-27-generic
-rw-r--r-- 1 40M mrt  9 09:55 initrd.img-5.13.0-28-generic
-rw-r--r-- 1 40M mrt  9 09:55 initrd.img-5.13.0-30-generic
-rw-r--r-- 1 45M mrt  9 12:02 initrd.img-5.13.0-35-generic
-rw-r--r-- 1 45M mrt 24 23:17 initrd.img-5.13.0-37-generic
-rw-r--r-- 1 45M mrt 30 17:49 initrd.img-5.13.0-39-generic
-rw-r--r-- 1 39M mrt  9 09:54 initrd.img-5.13.1-051301-generic
-rw-r--r-- 1 39M mrt  9 09:54 initrd.img-5.13.19-051319-generic
-rw-r--r-- 1 37M mrt  9 09:53 initrd.img-5.13.19-ubuntu-5.13.0-22.22
-rw-r--r-- 1 37M mrt  9 09:53 initrd.img-5.13.19-ubuntu-5.13.0-22.22-0-g3ab15e228151
-rw-r--r-- 1 37M mrt  9 09:52 initrd.img-5.13.19-ubuntu-5.13.0-22.22-317-g398351230dab
-rw-r--r-- 1 37M mrt  9 09:52 initrd.img-5.13.19-ubuntu-5.13.0-22.22-356-g8ac4e2604dae
-rw-r--r-- 1 37M mrt  9 09:52 initrd.img-5.13.19-ubuntu-5.13.0-22.22-376-gfab6fb5e61e1
-rw-r--r-- 1 37M mrt  9 09:51 initrd.img-5.13.19-ubuntu-5.13.0-22.22-386-gce5ff9b36bc3
-rw-r--r-- 1 37M mrt  9 09:51 initrd.img-5.13.19-ubuntu-5.13.0-22.22-387-g0fc979747dec
-rw-r--r-- 1 37M mrt  9 09:50 initrd.img-5.13.19-ubuntu-5.13.0-22.22-388-g20210d51e24a
-rw-r--r-- 1 37M mrt  9 09:50 initrd.img-5.13.19-ubuntu-5.13.0-22.22-388-gab2802ea6621
-rw-r--r-- 1 37M mrt  9 09:50 initrd.img-5.13.19-ubuntu-5.13.0-22.22-391-ge24e59fa409c
-rw-r--r-- 1 37M mrt  9 09:49 initrd.img-5.13.19-ubuntu-5.13.0-22.22-396-gc3d35f3acc3a
-rw-r--r-- 1 37M mrt  9 09:49 initrd.img-5.13.19-ubuntu-5.13.0-22.22-475-g79b62d0bba89
-rw-r--r-- 1 37M mrt  9 09:48 initrd.img-5.13.19-ubuntu-5.13.0-23.23
-rw-r--r-- 1 40M mrt  9 09:48 initrd.img-5.14.0-051400-generic
-rw-r--r-- 1 40M mrt  9 10:31 initrd.img-5.14.21-051421-generic
-rw-r--r-- 1 44M mrt  9 12:39 initrd.img-5.15.0-051500-generic
-rw-r--r-- 1 46M mrt  9 12:16 initrd.img-5.15.0-22-generic
-rw-r--r-- 1 46M mrt 28 23:27 initrd.img-5.15.32-051532-generic
-rw-r--r-- 1 46M mrt 17 21:12 initrd.img-5.16.0-051600-generic
-rw-r--r-- 1 48M mrt 28 23:19 initrd.img-5.16.16-051616-generic
-rw-r--r-- 1 45M mrt 28 23:11 initrd.img-5.17.0-051700-generic
-rw-r--r-- 1 46M apr  8 17:02 initrd.img-5.17.2-051702-generic
37
  • Versions 5.xx.yy-zz-generic are installed with apt.
  • Versions 5.xx.yy-05xxyy-generic are installed with the Ubuntu Mainline Kernel Installer.
  • Versions 5.xx.yy-ubuntu-5.13.0-zz.zz-nnn-g<commithash> are compiled from source, where <commithash> is the commit of the kernel repository that I compiled.

The kernels in bold are the kernels where something unexpected happens with my USB devices:

  • Ubuntu kernels 5.13.23 and up – including 5.15 kernels of Ubuntu 22.04 LTS (Jammy Jellyfish).
  • Ubuntu compiled kernels, starting 387 commits after kernel 5.13.22.
  • Mainline kernels 5.15.xx.

When Ubuntu finally bases their kernel on mainline 5.16 or higher, then the USB bug will be solved.

blur bright business codes

Install libssl3 on Ubuntu versions before Jammy

Ubuntu mainline kernel packages 5.15.7 and later bump a dependency from libssl1.1 (>= 1.1.0) to libssl3 (>= 3.0.0~~alpha1).

However, package libssl3 is not available for Ubuntu 21.10 Impish Indri. It’s only available for Ubuntu 22.04 Jammy Jellyfish (which is still in beta as of time of writing) and later.

libssl3 further depends on libc6>=2.34 and debconf, but they are available in 21.10 repositories.

Here are a few different ways to resolve the dependency:

Option 1

Use apt pinning to install libssl3 from a Jammy repo, without pulling in everything else from Jammy.

This is more complicated, but it allows the libssl3 package to receive updates automatically.
Do all the following as root.

  • Create an apt config file to specify your system’s current release as the default release for installing packages, instead of simply the highest version number found. We are about to add a Jammy repo to apt, which will contain a lot of packages with higher version numbers, and we want apt to ignore them all.
$ echo 'APT::Default-Release "impish";' \
    | sudo tee /etc/apt/apt.conf.d/01ubuntu
  • Add the Jammy repository to the apt sources. If your system isn’t “impish”, change that below.
$ awk '($1$3$4=="debimpishmain"){$3="jammy" ;print}' /etc/apt/sources.list \
    | sudo tee /etc/apt/sources.list.d/jammy.list
  • Pin libssl3 to the jammy version in apt preferences. This overrides the Default-Release above, just for the libssl3 package.
$ sudo tee /etc/apt/preferences.d/libssl3 >/dev/null <<%%EOF
Package: libssl3
Pin: release n=jammy
Pin-Priority: 900
%%EOF
  • Install libssl3:
$ sudo apt update
$ sudo apt install libssl3

Later, when Jammy is officially released, delete all 3 files created above

$ sudo rm --force \
    /etc/apt/apt.conf.d/01ubuntu \
    /etc/apt/sources.list.d/jammy.list \
    /etc/apt/preferences.d/libssl3

Option 2

Download the libssl3 deb package for Jammy and install it manually with dpkg -i filename.deb.

This only works if there aren’t any additional dependencies, which you would also have to install, with a risk of breaking your system. Here Be Dragons…

green and black industrial machine

Printing multiple PDF files from console with lp

Recently I wanted to print some PDF files containing sheet music. The tedious way to do that, would be to open them one by one in Evince and press the print button. Surely there must be a more efficient way to do that?

$ ls -l --human-readable *.pdf
-r--r--r-- 1 amedee amedee 217K apr 15  2020 'Arthur original.pdf'
-r--r--r-- 1 amedee amedee 197K apr 13  2020 'Canal en octobre.pdf'
-r--r--r-- 1 amedee amedee  14K apr 13  2020  DenAndro.pdf
-r--r--r-- 1 amedee amedee  42K apr 14  2020 'Doedel you do.pdf'
-r--r--r-- 1 amedee amedee  57K apr 13  2020  Flatworld.pdf
-r--r--r-- 1 amedee amedee  35K apr 16  2020 'Jump at the sun.pdf'
-r--r--r-- 1 amedee amedee 444K jun 19  2016 'Kadril Van Mechelen.pdf'
-r--r--r-- 1 amedee amedee  15K apr 13  2020  La-gavre.pdf
-r--r--r-- 1 amedee amedee  47K apr 13  2020 'Le petit déjeuner.pdf'
-r--r--r-- 1 amedee amedee 109K apr 13  2020  LesChaminoux__2016_04_24.cached.pdf
-r--r--r-- 1 amedee amedee 368K apr 13  2020 'Mazurka It.pdf'
-r--r--r-- 1 amedee amedee 591K apr 13  2020 'Narrendans uit Mater.pdf'
-r--r--r-- 1 amedee amedee 454K apr 13  2020 'Neverending jig.pdf'
-r--r--r-- 1 amedee amedee 1,1M apr 14  2020 'Red scissors.pdf'
-r--r--r-- 1 amedee amedee  35K apr 13  2020  Scottish-à-VirmouxSOL.pdf
-r--r--r-- 1 amedee amedee  76K apr 14  2020 'Tarantella Napolitana meest gespeelde versie.pdf'
-r--r--r-- 1 amedee amedee 198K apr 15  2020 'Zot kieken!.pdf'

There are 2 console commands for printing: lp and lpr. One comes from grandpa System V, the other from grandpa BSD, and both are included in CUPS. The nice thing about these commands is that they know how to interpret PostScript and PDF files. So this is going to be easy: just cd into the directory with the PDF files and print them all:

$ lp *.pdf
lp: Error - No default destination.

Oops. A quick Google search of this error message tells me that I don’t have a default printer.

Configuring a default printer

First I use lpstat to find all current printers:

$ lpstat -p -d
printer HP_OfficeJet_Pro_9010_NETWORK is idle.  enabled since za 12 mrt 2022 00:00:28
printer HP_OfficeJet_Pro_9010_USB is idle.  enabled since za 12 mrt 2022 00:00:17
no system default destination

I have a HP OfficeJet Pro 9012e printer, which Ubuntu recognizes as a 9010 series. Close enough. It’s connected over network and USB. I’m setting the network connection as default with lpoptions:

$ lpoptions -d $(lpstat -p -d | head --lines=1 | cut --delimiter=' ' --fields=2)
copies=1 device-uri=hp:/net/HP_OfficeJet_Pro_9010_series?ip=192.168.1.9 finishings=3 job-cancel-after=10800 job-hold-until=no-hold job-priority=50 job-sheets=none,none marker-change-time=0 media=iso_a4_210x297mm number-up=1 output-bin=face-down print-color-mode=color printer-commands=none printer-info printer-is-accepting-jobs=true printer-is-shared=true printer-is-temporary=false printer-location printer-make-and-model='HP Officejet Pro 9010 Series, hpcups 3.22.2' printer-state=3 printer-state-change-time=1649175159 printer-state-reasons=none printer-type=4124 printer-uri-supported=ipp://localhost/printers/HP_OfficeJet_Pro_9010_NETWORK sides=one-sided

I can then use lpq to verify that the default printer is ready:

$ lpq
HP_OfficeJet_Pro_9010_NETWORK is ready
no entries

Printing multiple files from console

I found that if I naively do lp *.pdf, then only the last file will be printed. That’s unexpected, and I can’t be bothered to find out why. So I just use ls and feed that to a while-loop. It’s quick and dirty, and using find+xargs would probably be better if there are “special” characters, but that’s not the case here.

There’s one caveat: when the PDF files are printed one by one, then the first page will be at the bottom of the paper stack, so I need to print them in reverse order.

$ ls --reverse *.pdf | while read f; do lp "$f"; done

With that command I got 17 print jobs in the printer queue, one for each file.

Now that I know how to print from console, I’ll probably do that more often. The man page of lp describes many useful printing options, like printing double sided:

$ lp -o media=a4 -o sides=two-sided-long-edge filename
laptop

Installing Ubuntu 20.04 LTS on 2011 MacBook Air

My laptop is a 2011 MacBook Air. I’m not a huge Apple fan, it’s just that at the time it had the most interesting hardware features compared to similar laptops. And it’s quite sturdy, so that’s nice.

Over the years I have experimented with installing Linux in parallel to the OS X operating system, but in the end I settled on installing my favorite Linux tools inside OS X using Homebrew, because having two different operating systems on one laptop was Too Much Effortâ„¢. In recent times Apple has decided, in it’s infinite wisdom (no sarcasm at all *cough*), that it will no longer provide operating system upgrades for older hardware. Okay, then. Lately the laptop had become slow as molasses anyway, so I decided to replace OS X entirely with Ubuntu. No more half measures! I chose 20.04 LTS for the laptop because reasons. 🙂

The laptop was really slow…

According to the Ubuntu Community Help Wiki, all hardware should be supported, except Thunderbolt. I don’t use anything Thunderbolt, so that’s OK for me. The installation was pretty straightforward: I just created a bootable USB stick and powered on the Mac with the Option/Alt (⌥) key pressed. Choose EFI Boot in the Startup Manager, and from there on it’s all a typical Ubuntu installation.

screenshot
Startup Manager

I did not bother with any of the customizations described on the Ubuntu Wiki, because everything worked straight out of the box, and besides, the wiki is terribly outdated anyway.

The end result? I now have a laptop that feels snappy again, and that still gets updates for the operating system and the installed applications. And it’s my familiar Linux. What’s next? I’m thinking about using Ansible to configure the laptop.

To finish, I want to show you my sticker collection on the laptop. There’s still room for a lot more!

sticker collection on my laptop. Photo copyright: me.