Results tagged “Linux”

I don't exactly know why but in the past month I somehow did not find the time and motivation to create a proper post but several things have happened and this is just a quick summary over them all.

This may or may not be followed by individual posts on each single subject. I hope that I get around to that but no guarantees. So lets get it on.

On the LED Cube front I hinted on a "recent technical acquisition" in my last post on that subject. Well, this acquisition is nothing less than a full blown digital oscilloscope. YAY. It took a few weeks to decide and also a few days to find a suitable distributor but now I'm a proud owner of an Owon SDS7102V 100MHz digital scope.

The next notable gadget I (finally) received is the long-awaited Pebble watch. Within two days this little gem became the most notable thing which I didn't know I have been missing as companion for my phone for a long time. Despite some bad reviews on other places, I've been expecting an "extension" to my phone's display and that's exactly what I got. No need to long for the phone in my pocket anymore when there's something up. Within a second I know what's up and can still decide if I should take out the phone or just ignore a received spam mail until later. Furthermore much less distraction for other participants in case of meetings. Currently I'm mainly using this Star Trek inspired watchface for displaying the time and I also have installed Pebble Notifier on my phone to forward notifications of some selected applications to the watch, even if these aren't natively supported by the Pebble app itself. Great tool. And it's quite exceeding the expected runtime, my current record is set at 10 days without recharge (and that's before I discovered the option to not turn on the backlight when there's enough ambient light).

I also attended several events. The first one was the Grazer Linuxtage which is a mixture of project exhibition and series of lectures all centered around Linux. Like two years ago, where I also attended, the lectures were quite interesting and I hope that I find some time to try out or have a deeper look at some things I noted down during the lectures. The only negative point of the event is that the place is getting much too small for this event. Many of the lectures I attended that day were so crowded that late-comers could not even enter the lecture hall anymore. I hope that this changes in the future.

One followup-event which I got notice of on the Linuxtage was a (Linux) Show and Tell at the realraum Graz. At this event people showcased their favourite or special Linux tools, i.e. special use cases and capabilities of SSH. Before that event I thought that I'm not that bad with the Linux console, but I've been pretty much floored by the experts there. Which is not necessarily as bad as it sounds because at least I understood everything the guys were talking about :)

The barcamp Graz was the next event which I visited. That time this was a three-day long event and luckily I could be there all days. A barcamp is like a conference just with the difference that every attendand is a participant and presenter. The detail topics of the sessions are not planned before but are decided on and ordered by all participants at the start of each day by themselves. It was a very interesting experience and made it possible to have a look at many different topics from many different points of view.

One special thing I took away from the barcamp was the idea of a Repair Cafe. This is a privately organized meetup of people to just repair broken everyday stuff and get some more lifetime out of it. It is some sort of counteraction against the creeping planned obsolescence of things. We were several people who were interested in that idea and it seems that Brigitte and I are currently the ones who are further driving the idea. Maybe there is the chance of a permanent recurring event where everyone helps everybody :)

Since Google Reader is discontinued by July 1st I've been looking for alternatives for some time now. I had a long look at Feedly but in the end didn't decide on it because it does not have a clean web interface but only works through native apps or browser plugins. So I chose to install Tiny Tiny RSS on my own. During installation I just hit a roadblock or two. In fact, my problems were that the minimum requirements for TT-RSS were PHP 5.3 and special server modes (e.g. no php_basedir/open_basedir restriction) while my hosting provider only offered PHP 5.2 with active open_basedir restriction. After trying to find an alternative to that (which wasn't successful) I decided to go the hard way and back-port and refactor Tiny Tiny RSS to work with my hosters restrictions. It took a few hours but finally I had a flawlessly running TT-RSS despite the settings of my hosting. I will post the changes here as soon as I come around to create a proper patchfile (maybe that will happen in the nearer future).

And finally last weekend I had the honor to be invited to my cousins wedding. It was a very nice and private wedding with (almost) only the closest relatives invited. Thanks for that and best wishes!


Yesterday noon the girlfriend of my brother called me on my mobile phone telling me that her laptop computer died. At first I thought, it would be no big problem. Plug in a Windows CD and run a repair phase on the computer should be the last thing to do to bring it back to working condition. Oh boy, how I underestimated the problem...

Quite soon after I had my first looks into the issue, apparently some broken driver file which is loaded about two seconds after the Windows startup screen and caused the laptop to reboot over and over, the first signs of the complexity of the problem became visible. When all my previous tries failed and I wanted to start a Windows-CD repair it didn't find any harddisks to repair. It has never happened to me before that Windows was unable to locate the harddisks, so I've been very puzzled.

When I booted a Linux-Live-CD the harddisk was visible and the NTFS-filesystem was accessible, so there was no problem on this side of the issue. It took me several attempts and investigation on the internet to finally realize, that it was the SATA-controller of this laptop which is not supported by Windows versions until Vista. And without access to the disk from windows, I couldn't chkdsk it, install a new copy of windows or do something else from a Windows-like environment.

I tried a lot of different aproaches after this point. Loading additional drivers during Windows CD startup, live-CD with BartPE builder, live-CD with UBCD4CD, both with and without XP SP3 slipstreamed, with and without included SATA/RAID and network drivers... Without success, the disk refused to be accessible from Windows. It became quite late in the evening and I decided to continue today.

After some thinking and checking back with her brother I suggested to her this afternoon to try a switchover to Linux, where there were no problems with missing drivers for hardware components. I expected to have to do some convincing but to the contrary, she immediately agreed and wanted to switch over. She was already working with a lot of Linux-ready software (Firefox, Thunderbird, OpenOffice, ...) so a switchover would not be such a big change. She's been very curious of trying to work with Linux and this seemed to be an ideal opportunity.

Well. And that's what we did this evening. Following the backup of the data with a live-CD I installed an Ubuntu 9.04 linux. It went without any issues worth to mention and now the laptop is linuxified and ready again to be used. Setup of Printer and WLAN were the larger ones but these did not stay for long.

The next steps will be to install the remaining applications, copy over the individual settings (eg. Firefox favourites) from the backup and setting up Wine for those applications which have no linux-counterpart. I don't expect any serious obstacles there anymore.


I've been tinkering on the problem of checking if an argument is numeric or not inside shell scripts for quite a time already. I searched the internet for a way to test if a variable in a bash script is consisting only of digits but haven't found a clear solution yet. Either that or I'm unable to bring up the right search terms. The main problem is that it has to be cross-Unix-compatible (Linux, Solaris, AIX).

A few weeks ago I completed an in-corporate eLearning course about Unix Shell Scripting. This course also contained lessons about basic Unix commands like sed and awk.

Today this tiny problem struck at me again and I tried to bring in my new knowledge from the course. What I came up with is:


# check first argument

# test if argument present, then compare original string to the string without non-digit characters
# if string is the same, it only consist of digits
if [ ! -z "$number" -a "$number" = "$(echo $number | sed 's/[^[:digit:]]//g')" ]
 echo "Argument is full numeric"
 echo "Argument is not full numeric"

I tested it and it seems to work on all the platforms I need it. I don't like the inline call of sed but for the sake of compatibility I'll settle with that.

Perhaps I'll find an easier solution in the future but now that's not a priority anymore...