Technology Tales

TypeError: unable to create a wrapper for GLib.Variant

A little while ago, I wrote a piece on here telling of how I got GNOME 3 installed an working on Linux Mint. However, I have discovered since that there was an Achilles heel in the approach that I had taken: using the ricotz/testing PPA so that I could gain additional extensions for use with GNOME Shell. If this was just a repository of GNOME Shell extensions, that would be well and good but the maintainer(s) also has a more cutting edge of GNOME Shell in there too. Occasionally, updates from ricotz/testing have been the cause of introducing rough edges to my desktop environment that have resolved themselves within a few hours or days. However, updates came through in the last few days that broke GNOME Tweak Tool. When I tried running it from the command line, all I got was a load of output that included the message that heads this posting and no window popping up that I could use. That made me see sense so I stopped living dangerously by using that testing repository. Apparently, there is a staging variant too but a forum posting elsewhere on the web has warded me off from that too.

Until I encountered the latter posting, I had not heard of the ppa-purge tool and it came in handy for ridding my system of all packages from the ricotz repository and replacing with with alternatives from more stable ones such as that from the gnome3-team. This wasn’t installed on my computer so I added it in the usual fashion by issuing the following command:

sudo apt-get install ppa-purge

Once that was complete, I executes the following command with the ricotz/testing repository still active:

sudo ppa-purge testing ricotz

Once that was complete and everything was very nicely automated too, GNOME Tweak Tool was working again as intended and that’s the way that I intend keeping things. Another function of ppa-purge is that it has excised any mention of the ricotz/testing repos from my system too so nothing more can come from there.

While I was in the business of stabilising GNOME Shell on my system, I decided to add in UGR too. First, another repository needed to be added as follows:

sudo add-apt-repository ppa:ubuntugnometeam/ppa-gen
sudo apt-get update

The next steps were to install UGR once that was in place so these commands were issued to do the job:

sudo apt-get dist-upgrade
sudo apt-get install ugr-desktop-g3
sudo apt-get upgrade

While that had the less desirable effect of adding games that I didn’t need and have since removed, it otherwise worked well and I now have a new splash screen at starting up and shutting down times for my pains. Hopefully, it will main that any updates to GNOME Shell that come my way should be a little more polished too. All that’s needed now is for someone to set up a dedicated PPA for GNOME Shell Extensions so I could regain drop down menus in the top panel for things such as virtual desktops, places and other handy operations that perhaps should have been in GNOME Shell from the beginning. However, that’s another discussion so I’ll content myself with what I now have and see if my wish ever gets granted.

Adding GNOME 3 to Linux Mint 11

On the surface of it, this probably sounds a very strange thing to do: choose Linux Mint because they plan to stick with their current desktop interface for the foreseeable future and then stick a brand new one on there. However, that’s what last weekend’s dalliance with Fedora 15 caused. Not only did I find that I could find my way around GNOME Shell but I actually got to like it so much that I missed it on returning to using my Linux Mint machine again.

The result was that I started to look on the web to see if there was anyone else like me who had got the same brainwave. In fact, it was Mint’s being based on Ubuntu that allowed me to get GNOME 3 on there. The task could be summarised as involving three main stages: getting GNOME 3 installed, adding extensions and adding the Cantarell font that is used by default. After these steps, I gained a well-running GNOME 3 desktop running on Linux Mint and it looks set to stay that way unless something untoward has yet to emerge.

Installing GNOME 3

The first step is to add the PPA repository for GNOME 3 using the following command:

sudo add-apt-repository ppa:gnome3-team/gnome3

The, it was a case of issuing my usual update/upgrade command:

sudo apt-get update && sudo apt-get upgrade && sudo apt-get dist-upgrade

When that had done its thing and downloaded and installed quite a few upgrades along the way, it was time to add GNOME Shell using this command:

sudo apt-get install gnome-shell

When that was done, I rebooted my system to be greeted by a login screen very reminiscent of what I had seen in Fedora. While compiling this piece, I noticed that GNOME Session could need to be added before GNOME Shell but I do not recall doing so myself. Maybe dependency resolution kept any problems at bay, but there weren’t any issues that I could remember beyond things not being configured as fully as I would have liked without further work. For the sake of safety, it might be a good idea to run the following before adding GNOME Shell to your PC.

sudo apt-get install gnome-session && sudo apt-get dist-upgrade

Configuration and Customisation

Once I had logged in, the desktop that I saw wasn’t at all unlike the Fedora one and everything seemed stable too. However, there was still work to do before I was truly at home with it. One thing that was needed was the ever useful GNOME Tweak Tool. This came in very handy for changing the theme that was on display to the standard Adwaita one that caught my eye while I was using Fedora 15. Adding buttons to application title bars for minimising and maximising their windows was another job that the tool allowed me to do. The command to get this goodness added in the first place is this:

sudo apt-get install gnome-tweak-tool

The next thing that I wanted to do was add some extensions so I added a repository from which to do this using the command below. Downloading them via Git and compiling them just wasn’t working for me so I needed another approach.

sudo add-apt-repository ppa:ricotz/testing

With that is place, I issued the following commands to gain the Dock, the Alternative Status Menu and the Windows Navigator. The second of these would have added a shutdown option in the me-menu but it seems to have got deactivated after a system update. Holding down the ALT key to change the Suspend entry to Power off… will have to do me for now. Having the dock is the most important and that, thankfully, is staying the course and works exactly as it does for Fedora.

sudo apt-get install gnome-shell-extensions-dock
sudo apt-get install gnome-shell-extensions-alternative-status-menu
sudo apt-get install gnome-shell-extensions-windows-navigator

Adding Cantarell

The default font used by GNOME 3 in various parts of its interface is Cantarell and it was defaulting to that standard sans-serif font on my system because this wasn’t in place. That font didn’t look too well so I set to tracking the freely available Cantarell down on the web.  When that search brought me to Font Squirrel, I downloaded the zip file containing the required TTF files. The next step was to install them and, towards that end, I added Fontmatrix using this command:

sudo apt-get install fontmatrix

That gave me a tool with a nice user interface but I made a mistake when using it. This was because I (wrongly) thought that it would copy files from the folder that I told the import function to use. Extracting the TTF files to /tmp meant that would have had to happen, but Fontmatrix just registered them instead. A reboot confirmed that they hadn’t been copied or moved at all and I had rendered the user interface next to unusable through my own folly; the default action on Ubuntu and Linux Mint is that files are deleted from /tmp on shutdown. The font selection capabilities of the GNOME Tweak Tool came in very handy for helping me to convert useless boxes into letters that I could read.

Another step was to change the font line near the top of the GNOME Shell stylesheet (never thought that CSS usage would end up in places like this…) so that Cantarell wasn’t being sought and text in sans-serif font replaced grey and white boxes. The stylesheet needs to be edited as superuser, so the following command is what’s needed for this and, while I used sudo, gksu is just as useful here if it isn’t what I should have been using.

sudo gedit /usr/share/gnome-shell/theme/gnome-shell.css

Once I had extricated my system from that mess, a more conventional approach was taken and the command sequence below was what I followed, with extensive use of sudo to get done what I wanted. A new directory was created and the TTF files copied in there.

cd /usr/share/fonts/truetype
sudo mkdir ttf-cantarell
cd ttf-cantarell
sudo mv /tmp/*.ttf .

To refresh the font cache, I resorted to the command described in a tutorial in the Ubuntu Wiki:

sudo fc-cache -f -v

Once that was done, it was then time to restore the reference to Cantarell in the GNOME Shell stylesheet and reinstate its usage in application windows using the GNOME Tweak Tool. Since then, I have suffered no mishap or system issue with GNOME 3. Everything seems to be working quietly and I am happy to see that replacement of Unity with the GNOME Shell will become an easier task in Ubuntu 11.10, the first alpha release of which is out at the time of my writing these words. Could it lure me back from my modified instance of Linux Mint yet? While I cannot say that I am sure of those but it certainly cannot be ruled out at this stage.

Extending ASUS Eee PC Battery Life Without Changing From Ubuntu 11.04

It might just be my experience of the things but I do tend to take claims about laptop or netbook battery life with a pinch of salt. After all, I have a Toshiba laptop that only lasts an hour or two away from the mains and that runs Windows 7. For a long time, my ASUS Eee PC netbook was looking like that too but a spot of investigation reveals that there is something that I could do to extend the length of time before the battery ran out of charge. For now, the solution would seem to be installing eee-control and here’s what I needed to do that for Ubuntu 11.04, which has gained a reputation for being a bit of a power hog on netbooks if various tests are to be believed.

Because eee-control is not in the standard Ubuntu repositories, you need to add an extra one for install in the usual way. To make this happen, launch Synaptic and find the Repositories entry on the Settings menu and click on it. If there’s no sign of it , then Software Sources (this was missing on my ASUS) needs to be installed using the following command:

sudo apt-get install software-properties-gtk

Once Software Sources opens up after you entering your password, go to the Other Software tab. The next step is to click on the Add button and enter the following into the APT Line box before clicking on the Add Source button:

ppa:eee-control/eee-control

With that done, all that’s need is to issue the following command before rebooting the machine on completion of the installation:

sudo apt-get install eee-control

When you are logged back in to get your desktop, you’ll notice a new icon in your top with the Eee logo and clicking on this reveals a menu with a number of useful options. Among these is the ability to turn off a number of devices such as the camera, WiFi or card reader. After that there’s the Preferences entry in the Advanced submenu for turning on such things as setting performance to Powersave for battery-powered operation or smart fan control. The notifications issued to you can be controlled too as can be a number of customisable keyboard shortcuts useful for quickly starting a few applications.

So far, I have seen a largely untended machine last around four hours and that’s around double what I have been getting until now. Of course, what really is needed is a test with constant use to see how it gets on. Even if I see lifetimes of around 3 hours, this still will be an improvement. Nevertheless, being of a sceptical nature, I will not scotch the idea of getting a spare battery just yet.

Enabling DVD playback in Ubuntu 9.04

This information is scattered about the web but I decided to collect something together in one place in case it helps anyone else. Here are two commands that appeared to do the deed for me:

sudo apt-get install ubuntu-restricted-extras totem-xine libxine1-ffmpeg libdvdread4

sudo /usr/share/doc/libdvdread4/install-css.sh

The libdvdread piece is what sorts out encrypted disks and needs a two stage installation, hence the second command. For non-encrypted disks, ubuntu-restricted-extras might be all that’s needed if my experience is typical. Taking things further, Wim Wenders’ Buena Vista Social Club (Region 2 disk) worked when I tried it too. In the interests of completeness, I tried the command combination on a virgin 9.04 installation with restricted and multiverse repositories enabled. Along the way, I spied a whole raft of helper components being set in place and things worked like I would have expected with the aforementioned DVD afterwards. As with anything related to computing, your mileage may vary and, for more information, you can take a look here.

Adding Microsoft core fonts to Debian

When setting up Ubuntu, I usually add in Microsoft’s core fonts by installing the msttcorefonts package using either Synaptic or apt-get. I am not sure why I didn’t try doing the same thing for Debian until now but it’s equally as feasible. Just pop over to System > Administration > Software Sources and ensure that the check-boxes for the contrib and non-free categories are checked like you see below.

You could also achieve the same end by editing /etc/apt/sources.list and adding the non-free and contrib keywords to make lines look like these before issuing the command apt-get update as root:

deb http://ftp.debian.org/debian/ lenny main non-free contrib
deb-src http://ftp.debian.org/debian/ lenny main non-free contrib

All that you are doing with the manual editing route is performing the same operations that the more friendly front end would do for you anyway. After that, it’s a case of going with the installation method of your choice and restarting Firefox or Iceweasel to see the results.

Ubuntu 9.04 and Tracker

Shortly after it was released, I did the upgrade shuffle very painlessly and it didn’t take up so much time either. There was only one issue: Tracker falling over complaining about corrupted indices. That got it removed from my system using apt-get remove (apt-get purge is another option, especially if you need to rid yourself of nefarious configuration files). After having a bit of a dig around the web, I found that I wasn’t the only one seeing the problem. To me, it looks as if the upgrade to 9.04 doesn’t work so well when it comes to Tracker and it needs to be removed and reinstalled to ensure that all required dependencies are correctly set in place. Since I restored it on my system all is working without complaint. Other than the Tracker issue, it has been a case of another uneventful upgrade. The evolutionary path that Ubuntu is following may disappoint anyone looking for excitement but no one would upgrade every six months if they knew that disruptive damage or upheaval might be caused. I may do a clean installation at some point but that is well down the priority list right now.

Ubuntu upgrades: do a clean installation or use Update Manager?

Part of some recent “fooling” brought on by the investigation of what turned out to be a duff DVD writer was a fresh installation of Ubuntu 8.10 on my main home PC. It might have brought on a certain amount of upheaval but it was nowhere near as severe as that following the same sort of thing with a Windows system. A few hours was all that was needed but the question as to whether it is better to do an upgrade every time a new Ubuntu release is unleashed on the world or to go for a complete virgin installation instead. With Ubuntu 9.04 in the offing, that question takes on a more immediate significance than it otherwise might do.

Various tricks make the whole reinstallation idea more palatable. For instance, many years of Windows usage have taught me the benefits of separating system and user files. The result is that my home directory lives on a different disk to my operating system files. Add to that the experience of being able to reuse that home drive across different Linux distros and even swapping from one distro to another becomes feasible. From various changes to my secondary machine, I can vouch that this works for Ubuntu, Fedora and Debian; the latter is what currently powers the said PC. You might have to user superuser powers to attend to ownership and access issues but the portability is certainly there and it applies anything kept on other disks too.

Naturally, there’s always the possibility of losing programs that you have had installed but losing the clutter can be liberating too. However, assembling a script made up up of one of more apt-get install commands can allow you to get many things back at a stroke. For example, I have a test web server (Apache/MySQL/PHP/Perl) set up so this would be how I’d get everything back in place before beginning further configuration. It might be no bad idea to back up your collection of software sources either; I have yet to add all of the ones that I have been using back into Synaptic. Then there are closed source packages such as VirtualBox (yes, I know that there is an open source edition) and Adobe Reader. After reinstating the former, all my virtual machines were available for me to use again without further ado. Restoring the latter allowed me to grab version 9.1 (probably more secure anyway) and it inveigles itself into Firefox now too so the number of times that I need to go through the download shuffle before seeing the contents of a PDF are much reduced, though not completely eliminated by the Windows-like ability to see a PDF loaded in a browser tab. Moving from software to hardware for a moment, it looks like any bespoke actions such as my activating an Epson Perfection 4490 Photo scanner need to be repeated but that was all that I needed to do. Getting things back into order is not so bad but you need to allow a modicum of time for this.

What I have discussed so far are what might be categorised as the common or garden aspects of a clean installation but I have seen some behaviours that make me wonder if the usual Ubuntu upgrade path is sufficiently complete in its refresh of your system. The counterpoint to all of this is that I may not have been looking for some of these things before now. That may apply to my noticing that DSLR support seems to be better with my Canon and Pentax cameras both being picked up and mounted for me as soon as they are connected to a PC, the caveat being that they are themselves powered on for this to happen. Another surprise that may be new is that the BBC iPlayer’s Listen Again works without further work from the user, a very useful development. It very clearly wasn’t that way before I carried out the invasive means. My previous tweaking might have prevented the in situ upgrade from doing its thing but I do see the point of not upsetting people’s systems with an overly aggressive update process, even if it means that some advances do not make themselves known.

So what’s my answer regarding which way to go once Ubuntu Jaunty Jackalope appears? For sake of avoiding initial disruption, I’d be inclined to go down the Update Manager route first while reserving the right to do a fresh installation later on. All in all, I am left with the gut feeling is that the jury is still out on this one.

Trying out Songbird

It’s amazing what can be done with a code base: the Gecko core of Firefox has been morphed into a music player called Songbird. On my Ubuntu machine, Rhythmbox has been my audio player of choice, yet the newcomer could be set to replace it. There might have been other things going on my system, but Rhythmbox playback was becoming jumpy and that allowed me a free hand to look at an alternative.

A trip to the Ubuntu repositories using Synaptic was all that was required to get Songbird installed. I suspect that I could have gone for an independent installation but the one that was available through the official channel sufficed for me. It found every piece of music in the relevant folder, even those that it was unable to play because of iTunes DRM and it was easy to set it such that it simply moved on when it met such a file rather than issuing a dialogue box to complain. That means that I weed out the incompatible entries in the course of time rather than having to do it straight away. I cannot claim to be an audiophile, but the quality of the playback seems more than acceptable to me and there seem to be no jumps so long as a file hasn’t been corrupted in any way. All in all, Rhythmbox could get usurped.

A quick way to do an update

Here’s a quick way to get the latest updates on your PC using the command line if you are using Ubuntu or Debian:

sudo apt-get update && sudo apt-get upgrade

Of course, you can split these commands up if you prefer to look before you leap. At the very least least, it’s so much slicker than the GUI route.

Cleaning up Ubuntu

Uninstalling software still leaves any dependencies that came with them in place so a quick way to get rid of any detritus is always useful. Here’s a command that achieves this in a painless manner:

apt-get autoremove

Just say yes to what it suggests to allow it on its way.