Steffen's Tech Blog

In Mac OS X you can take a screenshot of the complete screen by pressing Command-Shift-3 and a selection of the screen by pressing Command-Shift-4. This is usually sufficient enough, but if you try to use this key combination to capture a screenshot of a movie running in the Mac OS X DVD Player you will be surprised to find out that this doesn't work. The same is true for the built in Grab Application. If you still want to do capture a picture from a DVD you could use the screen-capture shell utility in the Terminal application - as described in several webpages. But if you would like something more convenient you could use an application such as Jing ( http://www.techsmith.com/jing/ ). It allows you not only to take a picture even from a movie running in the DVD Player but also to make a short videos of the your screen and provides several options to edit, save and share this pictures and videos afterwards. There is a Free version available a...

I am a fan of the free open source format 7z (see  http://en.wikipedia.org/wiki/7z ) for data compression and encryption. With keka ( http://www.kekaosx.com/en/ ) there is a nice, simple GUI application available for Mac OS X.

Assuming you have created a video file that you want to burn to a video DVD in Ubuntu. A nice and simple tool for this is DeVeDe  - a program to create video DVDs and CDs (VCD, sVCD or CVD), suitables for home players, from any number of video files, in any of the formats supported by  Mplayer . After you have created the .iso dvd image with DeVeDe you can easily burn it to the DVD using Brasero .

Recently I needed to combine two PDF documents that I created with the TurboScan App on my Iphone (file sizes 528.5 kByte and 421.9 kByte and was searching for free options I can use with Ubuntu Linux. I found the following options: The web service  http://www.mergepdf.net/ : Usability: Easy; excellent for merging PDF files Functionality: no other functions available File size of the merged file: 950.1 kByte The free online PDF editor PDF Hammer  http://www.nitropdf.com/free/hammer/index.htm . Usability: almost as easy as mergepdf Functionality: other functions available File size of the merged file: 949.8 kByte The Linux command line   pdftk too lkit:  http://www.accesspdf.com/pdftk/ Usability: follow examples on the webpage; easy if you are comfortable with the command line Functionality: other functions available File size of the merged file:  949.8 kByte The open source PDF editor PDFedit  http://sourceforge.net...

Yesterday I updated to the new Ubuntu 9.10 . The update was as usual very smoothly (I accepted the default values when ask something). After restarting, the following error message appeared: Starting Google Desktop manually via the application menu did work. Still, I had to reinstall Google Desktop  via Synaptic in order to avoid this error message during startup. The next message I got was: I clicked on "Run this action now", followed the instructions and the missing language components got installed. I used the following language settings: Afterwards I enabled the third party repositories again (in "Software Sources"): deb http://dl.google.com/linux/deb/ stable non-free deb http://linux.getdropbox.com/ubuntu karmic main deb-src http://linux.getdropbox.com/ubuntu karmic/ deb http://packages.medibuntu.org/ karmic free non-free deb-src http://packages.medibuntu.org/ karmic free non-free deb http://ftp.osuosl.org/pub/pculture.org/miro...

After I decided to scrap my more than 4 years old laptop, because it repeatedly failed after working some minutes after booting (when it fails, nothing worked usually any more than the mouse movement, sometimes even the screen display starts to blur; even booting from Live-CDs Ubuntu 8.10, etc. showed the same effect), I was looking for a secure way to delete all data. I settled with: shred -vfz -n 10 /dev/hda" from stackoverflow.com , I had to use a very small Linux distribution ( DSL ), that was running completely in the RAM in order to be able to start the shred command (with other Live-CD's the laptop was failing already before I was able to start the command via a shell). Update: This command was running nearly one week. At the end I tried to verify the success by removing the Live-CD and start to boot again. To my surprise, Ubuntu was still booting. I am still not sure, how to explain this. Anyway, I decided to remove the HD and destroy it mechanically. That shoul...

As my 500GB Time Capsule has reached the limits (my Macbook and the iMac of my wife used it as backup destination for Time Machine ), I decided to buy another backup drive and settled with the Western Digital WDH1NC10000E My Book World Edition 1TB NAS external drive. The main advantage (besides the price: I bought it fo r EUR 146,95 (incl. VAT and free transportation) for me was that I could easily connect it to a free Ethernet port of my Time Capsule - at least that was what I did expected. But after I connected the My Book to my network as discribed in the My Book manual, I had to discover that although it was available in the finder and I could manually copy files to it, it wasn't available in Time Machine as a back up destination. Furtunately obvioulsly others experienced this problem before and after some googling I came to the solution described in the post "Time Machine backups on network shares in Leopard" from Florian Kruse. Following the steps described the...

I just followed the network upgrade instructions for Ubuntu Desktops (Recommended) and accepted the default values for the questions I was asked by the update tool (e.g. disable the proprietary display driver and use the default open source driver instead). Everything went smoothly. Afterwards I enabled the third party repositories again: http://dl.google.com/linux/deb/ stable non-free http://linux.getdropbox.com/ubuntu jaunty main http://packages.medibuntu.org/ jaunty free non-free The dropbox demon wasn't running, I had to install it again with dropbox start -i I realized that my backup python script using rsync didn't work any more, so that I had to install it again with: ~/Documents/Programming/Python_scripts/backup_daily$ sudo python setup.py install Afterwards, I could enjoy the improvements and new features of Ubuntu 9.04

I tried Dropbox - a cool file-synchronization service for Windows, Mac, Linux and the Web - after hearing about it on the Macworld Video Podcast Episode from Jason Snell from Feb 13, 2009 and loved it since. Dropbox allows you to sync (and - if you want share) up to 2GB of your files and folders automatically (and for free!) simply by dragging and dropping them into the Dropbox folder that will be created by the application (by default under your home directory). If you need more space you can buy 50GB of storage for currently US$99/year. I'm impressed how easy and fast the web-based synchronization works and was amazed that it works cross-platform - even an Ubuntu repository is available. I use it now to synchronize a few files I often need on my Ubuntu desktop, my macbook and my wife's iMac. If it works as reliable as it has done in the first days I am using it and if there will be a more cheaper storage plan version (e.g. 25GB for US$49/year), I might use it even to back...

In the last months I have spent some time trying out different GUI toolkits for Python that are cross-platform (Linux, Mac OS X and Windows). I settled with PyQt . It combines Nokia's Qt cross-platform application framework with Python so you get all the power of Qt with the simplicity of Python. Other Desktop GUI frameworks I have tried are: the Tk GUI development library included in most Python distributions wxpython a blending of the wxWidgets C++ class library with Python PyGTK to use the GTK+ library Others (such as .NET using IronPython ) are not running equally good on Linux, Mac OS X and Windows as they favour Windows. From the frameworks above, PyQt  seemed the one with the most active development, the most easy usage and the best documentation. Like Qt, PyQt V4 (its newest version) is available under a variety of licenses including GNU GPL (V2 and V3; today Qt Software announced that Qt V4.5 will also be available under LGPL). If you want to write commercial applicat...

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Did you ever want to download Web videos from sites such as YouTube or others (such as http://www.vidohe.com/sites.php )? Firefox 3.0 together with the free Firefox extension DownloadHelper makes this very easy (see the DownloadHelper homepage for more details). DownloadHelper even provides a Video Conversion feature to allow background conversion of the downloaded video to the format that you like (e.g. from FLV to a format that can be used by iTunes e.g. to load on your iPod or iPhone). This feature relies on FFMPEG available on your system (for Linux or Mac), which can lead to conversion failures as the version of FFMPEG may not have been compiled with the features required by the chosen conversion parameters. You can therefore recompile FFMPEG by yourself with the required features. Note: With Ubuntu 9.10 - the Karmic Koala - there is no need to recompile FFMEG. It just works fine. As an alternative, you can use an external application such as MPEG Streamclip ...

Two weeks ago I upgraded to Ubuntu 8.10 (Intrepid Ibex). The upgrade went nice and smoothly and I really like the new version (especially the improvments made in KDE). The only problem I realized afterwards was that the Skype audio settings wasn't working correctly by default. Some manual adjustments were necessary. After I have done these adjustments already several times (two PC's, GNOME and KDE), I thought it might make sense to write them down. Maybe these settings that worked for my PC's will be helpful somebody else. adjust the skype sound device options as shown in the following screenshot: adjust the Ubuntu audio settings (Volume control) according to the next 4 screenshots:

The newest version of my favorite Linux distribution ...

Following the instructions on KDE 4.1.1 Release News I updated to KDE 4.1.1 on my Kubuntu 8.04 Hardy Heron PC. Some of the instructions were a little confusing: enable "Recommended Updates (backports)" in "Software Sources" --> as "backports" are also used to describe "Unsupported updates" (--> which is not recommended for a productive system), it must be a mistake There is no authentication key for the repository containing the updated packages deb http://ppa.launchpad.net/kubuntu-members-kde4/ubuntu hardy main . This results in warnings when updating packages from this repository which leave some kind of uneasiness as using authentication keys seem an useful security measure. Besides this, the update worked well and I found now KDE 4.1.1 much more stable than KDE 4.0. In addition, most of the functionality that I used in the GNOME desktop is available. Furthermore  I like the new KDE look as well as some of its new applications (as alrea...

Two weeks ago my MacBook wouldn't start because of a hard disk defect. As the Macbook still was within the warranty period, I took it to the nearest Apple authorized service provider A.S.T.I. GMBH AGENTUR FÜR SYSTEME (that I have found via http://www.apple.com/de/buy/locator/index.html ), where they replaced the HD. At home, I restored my Macbook HD content (that furtunately had been regularly backed up via Time Capsule) with the following steps (based on http://support.apple.com/kb/HT1177 ): Install the system from the Mac OS X 10.5 Leopard DVD Restart the Mac Connect Time Capsule via an Ethernet cable with the Macbook Click "From a Time Machine backup or other disk." when asked if you want to transfer information from another Mac or volume (in the Do You Already Own a Mac?" window). Click Continue Select Time Capsule when it appears as a Backup Volume and click Continue The Macbook starts to check the Time Machine backup and the "Transfer Your Information...

Recently I needed a tool to modify PDF files and afterwards merge these files into one file. I ended up using the following tools: Inkscape Inkscape is a free and open source vector graphics editor that can be used - among lots of other functions - to modify a single PDF page (e.g. add text). AccessPDF - Pdftk the PDF Toolkit. Pdftk is a free and open source easy to use command line tool for: * Merge PDF Documents * Split PDF Pages into a New Document * Decrypt Input as Necessary (Password Required) * Encrypt Output as Desired * Fill PDF Forms with FDF Data and/or Flatten Forms * Apply a Background Watermark * Report on PDF Metrics such as Metadata, Bookmarks, and Page Labels * Update PDF Metadata * Attach Files to PDF Pages or the PDF Document * Unpack PDF Attachments * Burst a PDF Document into Single Pages * Uncompress and Re-Compress Page Streams * Repair Corrupted PDF (Where Possible) e.g. the following example Merges Three PDFs...

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Recently, I spent some time to search for free, open-source alternatives for commercial mathematics programs such as Matlab and Mathcad. By far the most promising software I have found was Sage. Sage combines the power of many (currently 71) existing open-source packages into a common Python-based interface. It can be used to explore mathematical constructions in algebra, geometry, number theory, calculus, numerical computation, etc. The combination of proven open-source packages (including excellent Python packages such as Numpy, Matlibplot, Scipy and Sympy) and an excellent web browser based entry of formulas and plots in worksheets called notebooks. The usage of Python as the glue that holds all packages together provides several advantages. First you have the full power of python available in Sage. Second, you don't need to learn another specialized script language that you would otherwise not need. Excellent screencasts together with good tutorials and documentation pages p...

After reading the following article about the status of the GNOME project http://wingolog.org/archives/2008/06/07/gnome-in-the-age-of-decadence I decided to check out the KDE 4 desktop by installing the "kubuntu-kde4-desktop" package (via Adept or apt-get) and I have to admit: I really like the new KDE 4 desktop. A lot of improvements have been made compared with its predecessor. I especially like the new version of the image viewer Gwenview and Okular, KDE4's document viewer. Check out http://www.kde.org/announcements/4.0/applications.php for more details. Unfortunately, the KDE 4 desktop seem not to be stable enough for production use. At least I experienced some crashes that required reboot via " R aising E lephants I s S o U tterly B oring" . In addition, I missed some functionality. Therefore I can't recommend switching to KDE4 right now. But I decided to give it another try as soon as KDE4.1 is available from the Ubuntu repositories in the hope that ...