pdflatex not found. Please select a different –pdf-engine or install pdflatex

If you use pandoc to generate a pdf file from a markdown file, you may have this warning message :

pdflatex not found. Please select a different –pdf-engine or install pdflatex

On Ubuntu 19.04, after an initial install using the distribution package manager, no pdf engine is installed.

Using the apt-file utility and searching for pdflatex, texlive-latex-base package includes it.
This package texlive-fonts-recommended will bring additional fonts.

To install it :

apt install textlive-latex-base texlive-fonts-recommended

To test the pdf output :

pandoc test.md -s -o test.pdf



What is java.awt.headless ?

As well detailed in the article below,

Java contains a lot of classes which assume that there is a some sort of display and a keyboard attached. Sometimes, you are writing code to run on a server which does not have these and this is called Headless mode

For some Java-based web applications, graphics can be generated. Either you need to configure the application to use the local X Window server or use the Java Headless option.

Source : https://blog.idrsolutions.com/2013/08/what-is-headless-mode-in-java/

Use case example for headless image processing : https://github.com/processing/processing/wiki/Running-without-a-Display

javaldx: Could not find a Java Runtime Environment! on Ubuntu 18.04.1

Running LibreOffice from the shell can display this message :

javaldx: Could not find a Java Runtime Environment!
Please ensure that a JVM and the package libreoffice-java-common
is installed.
If it is already installed then try removing ~/.libreoffice/3/user/config/javasettings_Linux_*.xml
Warning: failed to read path from javaldx
func=xmlSecCheckVersionExt:file=xmlsec.c:line=188:obj=unknown:subj=unknown:error=19:invalid version:mode=abi compatible;expected minor version=2;real minor version=2;expected subminor version=25;real subminor version=26

This solution suggests installing libreoffice-base ubuntu package to fix it. It will also install libreoffice-java-common package while managing all the required dependencies.
Installing it removes this error message permanently On Ubuntu 18.04.1

NB : This solution works as well for Ubuntu 19.04

Pocket button does not save any urls

Saving urls using the Pocket Pocket service service has failed within Firefox.
I am running the Windows 7 version of firefox with a couple of useful extensions.
The Pocket account has already been set up and authentication to the Pocket service works fine.
To make it work again, all the addons and extensions have been disabled for troubleshooting. No success.
I had to reinstall Firefox and delete my profile as indicated below :
How to successfully uninstall Firefox under Windows 7

Once completed and after adding the Pocket button into the firefox toobar, Saving urls with the Pocket service works fine again.

More information here :
Saving to Pocket and Accessing your List in Firefox