Could not launch application ‘blueman.desktop’: Unable to start application: Failed to execute child process “blueman-applet” (No such file or directory)

After an upgrade from Debian 9.9 to Debian 10, some errors were found in my .xsessions-errors file.

The apt-file utility provided by the Debian distribution provides an easy way to provide the matching Debian package for a given file.

To install it :

apt install apt-file

To provide it with the latest details from Debian repos :

apt-file update

To look for the corresponding Debian package that blueman.desktop file belongs to :

apt-file search blueman.desktop
blueman: /etc/xdg/autostart/blueman.desktop
blueman: /usr/share/Thunar/sendto/thunar-sendto-blueman.desktop

To install it :

apt install blueman

More details :

Details of apt-file Debian package

Details of blueman Debian package

Advertisements

Could not launch application ‘hplip-systray.desktop’: Unable to start application: Failed to execute child process “hp-systray” (No such fil e or directory)

After an upgrade from Debian 9.9 to Debian 10, some errors were found in my .xsessions-errors file.

The apt-file utility provided by the Debian distribution provides an easy way to provide the matching Debian package for a given file.

To install it :

apt install apt-file

To provide it with the latest details from Debian repos :

apt-file update

To look for the corresponding Debian package that hplip-systray.desktop file belongs to :

apt-file search hplip-systray.desktop
hplip-gui: /etc/xdg/autostart/hplip-systray.desktop

To install it :

apt install hplip-gui

More details :

Details of apt-file Debian package

Details of hplip-gui Debian package

To detect whether software based rendering is needed for Qt 5 the glxinfo program is a requirement but it was not found on this system.

After an upgrade from Debian 9.9 to Debian 10, some errors were found in my .xsessions-errors file.

To detect whether software based rendering is needed for Qt 5 the glxinfo program is a requirement but it was not found on this system.

The glxinfo program is provided by the mesa-utils Debian package.

To install it :

apt install mesa-utils

More details : Details of mesa-utils Debian package

Fix auto-indentation in Vim

Here are a few VIM commands to type within the editor to check the current settings and enable what is missing to make VIM auto-indent your file.

:filetype

If disabled, the output will be :

filetype detection:ON plugin:ON indent:OFF

To enable it :

:filetype indent on

To list all the indentations file available (for any programming language for instance)

:e $VIMRUNTIME/indent

If you find one that matches the programming language that you are typing in your editor, to indent your code :

gg=G

To make it permanent, add the following line in your .vimrc file :

filetype indent on

UTF-8 handling in Perl for I/O (Wide character in say at)

If you handle UTF-8 I/O streams in Perl and if this is not explicitly activated either as argument of your Perl interpreter or within your Perl script, you can have this warning :

Wide character in say at

If you enable the pragma use diagnostics, more details will be provided for this warning :

Wide character in say at
(S utf8) Perl met a wide character (ordinal >255) when it wasn’t
expecting one. This warning is by default on for I/O (like print).

If this warning does come from I/O, the easiest
way to quiet it is simply to add the :utf8 layer, e.g.,
binmode STDOUT, ‘:utf8’. Another way to turn off the warning is
to add no warnings ‘utf8’; but that is often closer to
cheating. In general, you are supposed to explicitly mark the
filehandle with an encoding, see open and “binmode” in perlfunc.

If the warning comes from other than I/O, this diagnostic probably
indicates that incorrect results are being obtained. You should examine
your code to determine how a wide character is getting to an operation
that doesn’t handle them.

This StackOverflow answer provides a way to activate UTF-8 on I/O as as a command-line flag -CS : https://stackoverflow.com/questions/15210532/use-of-use-utf8-gives-me-wide-character-in-print

-CS enables UTF-8 on the Perl I/O on all the filehandles (STDIN, STDOUT and STDERR).

To enable this feature within your Perl script, use open “perl pragma to set default PerlIO layers for input and output” :

use open qw(:std :utf8);

More details :

Perl documentation : open perl pragma

Perl Unicode Cookbook : Make All I/O Default to UTF-8

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

How to keep date and time up to date after resuming from sleep mode

If you’re running Ubuntu Linux within a VM, time and date may not be accurate after resuming from sleep mode.

timedatectl provides a way to display and modify date and time information.

To get full details about the current date/time/time zones settings :

timedatectl status

Syncing date and time information with a ntp server is relevant.

timedatectl set-ntp true

To see the modification in effect :

timedatectl status

The NTP service information should be updated from inactive to active.