Monthly Archives: May 2012

Ubuntu 12.04 LTS Precise Pangolin – gnome-shell does not start

After activating the Screen Keyboard in the Typing tab of the Universal Access dialog in System Settings, my Gnome Shell display freezed. After restarting the X server and logging into my account, the Gnome Shell refused to load. I ended up staring at the default background image and after a while, apport proposed to submit a bug report about a crash in gnome-shell (due to XML input).

In .xsession-errors, I found another hint, that gnome-shell crashed (mind the last line!)

gnome-session[2146]: WARNING: Application 'gnome-shell.desktop' killed by signal
gnome-session[2146]: WARNING: Application 'gnome-shell.desktop' killed by signal
gnome-session[2146]: WARNING: App 'gnome-shell.desktop' respawning too quickly
gnome-session[2146]: CRITICAL: We failed, but the fail whale is dead. Sorry....

and dmesg hinted at a problem in XML input just as apport suggested,

gnome-shell: segfault at 0 ip 00007f5aefcda85e sp 00007fff17afac60 error 4 in libxml2.so.2.7.8[7f5aefc8d000+151000]
gnome-shell: segfault at 1f730a0 ip 0000000001f730a0 sp 00007fffce54ffc8 error 15

Suspecting that the activated screen keyboard is the problem, start a Gnome Classic (No Effects) session. For this, click on the small wheel icon in the top right corner of your login box. In Gnome Classic, revert your screen keyboard settings in the system settings dialog and deactivate the screen keyboard.

This will let you login to the Gnome Shell again.

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drwright – A typing break application for Gnome and Unity on Ubuntu 12.04

Having worked on computers for years, I learned to appreciate typing break applications that remind me regularly of focussing my eyes on something else than the screen in front of me. Moreover, giving the hands a break from typing is a recommended prevention from Repetitive strain injuries (RSI). As break remainders popping up dialogs turned out to be ineffective for me, I soon started to use applications blocking the entire screen for a certain amount of time. This post shortly describes how to install such a typing break application for Gnome 3 and Unity on Ubuntu 12.04.

On Gnome 2, a native typing break plugin included in gnome’s core did a wonderful job. This plugin did not make it into gnome 3, and I have used good old xwrits as a replacement for nearly a year now. With Ubuntu 12.04, I was having another look around: I have used workrave  before on Windows, and as it still does not support locking the entire screen, workrave is not an option. The more I was excited to learn about drwright. This is the original Gnome 2 typing break plugin that is now continued as actively developed and separate component for Gnome 3 and Unity.

Drwright is not included in the main Ubuntu distribution but is availble through a PPA.
I shortly repeat the installation steps here to install and configure drwright.

Add the PPA’s package source to your sources list:

sudo add-apt-repository ppa:drwright/stable

(This step requires root privileges, so enter your superuser password when asked to do so)

Update your system’s list of available packages:

sudo aptitude update

Install drwright

sudo aptitude install drwright

Log out and log back into gnome to finally find a new icon in the Personal section of your gnome system settings (Applications -> System Settings) called Typing Break.

And in case you ever need back screen access during a typing break, change to the console (ctrl alt F1), login and kill the drwright process,

sudo killall /usr/lib/drwright/drwright/gnome-typing-monitor.

TeX Live on Ubuntu – Why fontspec does not work with LuaLaTeX on Ubuntu 12.04

Recently, I was catching up with developments in the TeX world. With xetex and luatex being serious replacements for good old pdftex by now, I wanted to give them a try on a recent Ubuntu machine. Trying to compile this minimalistic lualatex code

\documentclass{article}
\usepackage{fontspec}
\begin{document}
The quick brown fox jumps over the lazy dog.
\end{document}

I ended up with the error message

********************************************
* XeTeX is required to compile this document.
* Sorry!
********************************************

Wondering, what the problem might be, I learned that fontspec was originally developped for XeTeX. lualatex support was added with version 2.0 released in 2010.

When it comes to LaTeX support, Debian (and with it Ubuntu) include the TeX Live distribution. Being one of the most popular LaTeX distributions, TeX Live included the new fontspec packages from version 2010 onwards. However, as of Ubuntu 12.04 LTS Precise, the TeX Live packages are
still at version 2009.

As reasons for this, the immense packaging work necessary to get TeX Live into Debian is quoted, see here for example. This means that without further ado, LuaLaTeX on Ubuntu will not work with fontspec (and will be pretty outdated anyway).

The good news is that things are about to change. In March 2012, the latest TeX Live packages entered Debian experimental and started their way through the Debian package queue. At the time of writing, they made it to unstable; unfortunately too late to enter Ubuntu 12.04. From what I know about the Debian to Ubuntu package updates, chances are good a recent TeX Live version will make it into the next Ubuntu version 12.10.

In the meantime, you will find instructions on how to directly install TeX Live on Ubuntu or, if you are using an i386 system, may use the TeX Live backports from this Ubuntu PPA.