Some days ago I discovered galternatives, a GNOME tool to manage the alternatives system of Debian/Ubuntu. It’s really smart I think.

For example to update the default editor for your system you need to update the alternatives system via:

update-alternatives --set editor /usr/bin/vim

There is also an interactive version available:

update-alternatives --config editor

To see available browsers you need to run

update-alternatives --list x-www-browser

However, the alternatives system is a nice idea I think, but it’s a bit confusing sometimes. And installing a new group or adding another entry to an existing group is pretty complicated and requires information from multiple other commands beforehand.

With galternatives you’ll get a graphical interface to manage all these things. That really brings light into the dark! Just install it via

aptitude install galternatives

You’ll be astonished if you give it a try! ;-)

YOURLS Firefox Extension Version 1.4

I submitted a new version of the YOURLS Firefox extension.

It just contains some minor changes, but I want to inform my loyal readers! The add-on is currently in the review queue, hopefully this time I’ll get a complete review by the AMO-team ;-)

If you’re crazy you can try the new version, it’s available on SourceForge and on AMO.

UPDATE: I just received a fully review, so my add-on is finally stable!!

J-vs-T goes Java

I just ported the Jabber -vs- Twitter bridge to Java.

That was a point on my todo list for a long time, because I hate the hacked stuff from the improvised Perl solution. And in the end I finally did it ;-)

You can find the new XMPP to Twitter bridge with the name XTB in my sidebar. It’s now written in nice Java code, easy to understand and much easier to work with! So feel free to give it a try!

End of announcement! :P


Some days ago IonHunter came into the world!

IonHunter is the tool I’m actually developing to receive one of these diplomas. It’s is a software to identify biomarkers in a huge number of LC/MS runs. IonHunter is able to preprocess mass spectrometry data, to merge multiple runs of the same sample and also to correct retention time shifts to align various experiments.

The whole software is modularly designed and easy to extend with further plugins. So developers feel free to join my development!

Currently it isn’t published, but since it’s written in Java it will run on nearly all operating systems. We focused on usability and comfort for mass spec scientists, who will use the tool.

This is just a small announcement for the recently launched website, you might want to take a look at it!? (-;

Small hint for my faithful readers: Subscribe to IonHunters newsletter to stay informed and miss no release!

Presentation using two screens

Yesterday I attended a presentation of a colleague, but unfortunately during his speech the PDF viewer on his laptop crashed.

His supervisor told him to use pdf_presenter_console . Don’t know whether you’ve already heard about this tool? It’s able to display the current slide on the beamer-screen while you can see the next slide on your real screen. Generally a nice idea, but the software seemed to be a bit unstable ;-)

Anyway, I always wanted to find a solution to see some notes for a single slide while the slide is active, and today I set to work.

I searched for tools that are able to open two different PDF’s at once, I tried impressive, some vnc hacks, and so on, until I realized that there is already a smart solution on my laptop using the lightweight PDF viewer XPDF!

XPDF has a nice remote feature, if you run it like

xpdf -remote SOMEID presentation.pdf &

you can use your terminal to send some commands to the viewer. For example to go to the next slide try the following (see the COMMANDS section of XPDFs man page):

xpdf -remote SOMEID -exec nextPage

Great, isn’t it!? (if you receive the error error: "nextPage" file not found scroll down to XPDF is buggy)

I think the rest is clear, open two different XPDF-instances, one for the notes and one for the presentation itself:

usr@srv % xpdf -remote NOTES notes.pdf &
usr@srv % xpdf -remote PRESENTATION presentation.pdf &

and define some keys to scroll through the PDFs. You could use xbindkeys to bind the keys to the commands, for example I use F9 to go to the next slide and added the following to my ~/.xbindkeysrc :

"xpdf -remote PRESENTATION -exec nextPage && xpdf -remote NOTES -exec nextPage"
    m:0x10 + c:75

After running

xbindkeys -f ~/.xbindkeysrc

I’m able to go to the next slide by pressing F9 . To find the keycodes for some keys you may use xbindkeys -k or xev . Take a look at the documentation for more information (GER). Of course presentation.pdf and notes.pdf should have the same number of pages ;-)

XPDF is buggy

The -exec flag didn’t work for me, returning the following error:

usr@srv % xpdf -remote SOMEID -exec nextPage
error: "nextPage" file not found

I tried version 3.02 and also 3.03. The problem is located in the XPDF wrapper script, located in /usr/bin/xpdf . If you take a look at the contents you’ll find the following lines (in my case it’s 25ff):

while [ "$#" -gt "0" ]; do
    case "$1" in
        cmd="$cmd $1 "$2"" && shift ;;
        title="$2" && shift ;;

They simply forgot to define the -exec parameter to take an argument. So nextPage is not seen as argument for -exec and XPDF tries to find a file called nextPage that is obviously not present. To patch this you just need to add -exec like:

while [ "$#" -gt "0" ]; do
    case "$1" in
        cmd="$cmd $1 "$2"" && shift ;;
        title="$2" && shift ;;

or just use xpdf.real directly and skip the wrapper:

usr@srv % xpdf.real -remote SOMEID -exec nextPage

Since modifying files in /usr/bin isn’t a good idea I recommend to just substitute xpdf for xpdf.real in your ~/.xbindkeysrc .

That’s it for the moment, I wish you a nice presentation ;-)

Martin Scharm

stuff. just for the records.

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