i got this error message whenever I tried to call zenity in a cron job of a user. I found some hints in the net but still failed. But's its just 2 commands you have to add.


You most probably didn't notice the green lock in your browser when you visit this website. Access to any page of this website is now redirected to HTTPS and thus any data will be transferred encrypted all the time. There are no creditcard numbers or other sensible information transferred from and to this website. Edward Snowden fortunately made us aware that there are people unseen listening on the internet traffic. There is no need to secure any access to this webpage but nevertheless every access is now encrypted and secure.

Qualsys SSL reports the rating of the ssl encryption as A

Today I found in c't 22/2014 22/2014 (German computer journal) a nice article with the same title. Examples show how easy you can combine various commandlien tools in Linux and follow the Unix Philosophy and manipulate without any Programming text files, split and join them. Applications are to process csv files, log files or word frequency analysis and much more. recently I had a similar problem with text files which I solved using most of the tools mentioned in the article. But I was suprosed to read that the tools are much more powerful when you use special parameters. It's a good idea to read the man pages of the tools. On following pages I summarized all tools together with their most powerful parameters.

Today I installed Linux Mint 10 on my box. It's a nice Linux distro which runs out of the box  on various hardware. The following pages contain a summary of the experiences I made with different video player with my dvb-s Pinnacle TV SAT (BT878 based) on Linux Mint 10. My goal was to get a player configured very quickly (< 15 mins) and not to read much doc about the player in the net. Right now I know kaffeine which I used on an openSuSE box previously.

Important data has to be backed up in professional environments and even at home where you have important photos, videos, documents, eMail etc which you don't want to loose. There exist a lot of tools on Linux (rsync, rsnapshot ...) to create backups. From time to time you should check whether the backup is identical with the original. It's uggly if you detect the backup is not complete when you actually need the backup.

When I installed Mint 17 (Quiana) my boot menu had to be updated. Unfortunately the Grub Customizer was missing. I installed it with

  1. sudo add-apt-repository ppa:danielrichter2007/grub-customizer
  2. sudo apt-get update
  3. sudo apt-get install grub-customizer

I found the information on this site which also has other useful hints about steps to execute after a Mint installation. So it's worth to visit this page.

From time to time you have to use and configure grub. If you don't do it every day you forget a lot of details about grub. I found a very helpful and comprehensive Webseite in Englisch from Jodeep Bakshi. A nice tutorial about grub2 is here available.


Some time ago somebody told me about 'screen' in an irc chat. He just started to use screen and enjoyed the power of this command and wanted to share this experience with me. I now use this tool very often when I work on a remote system and other people should be able to follow the command I entered and which results I get. This was in particular useful when people asked for help because they had issues with Linux and they allowed me to access their system. That way they easily were able to follow all the activities I executed on their system. But it's also for other tasks very helpful and I now use it quite often.
I just checked the man page of screen and detected there are much more features available. I summarize the features on the following pages and list useful keyboard shortcuts.

Some time ago I liked to play Little Big Adventure (LBA und LBA2) on DOS: It's a nice and amusing game.  Recently I detected both CDs in my shelf and thought it would be great to play these games again.

nmap is a powerfull tool, which is known to be a port scanner. But there are other useful situations where it can be used:

  1. Query dhcp parameters
    sudo nmap -sU -p 67 --script=dhcp-discover
  2. Query registered DNS names in a fritz box
    sudo nmap -sP -PN -R --dns-servers | grep -i fritz.box

From time to time a Linux user want's to get a more detailed view about his system: That will be CPU utilization, netowkr information, disks and IO etc. On Linux fortunately there are a lot of different tools available.