How to install and configure latest Oracle JDK in Fedora

Most parts of this How-To have been taken from http://www.if-not-true-then-false.com/2010/install-sun-oracle-java-jdk-jre-7-on-fedora-centos-red-hat-rhel/

1. Check Java version
   $ java -version
java version "1.7.0_05-icedtea"
OpenJDK Runtime Environment (fedora-2.2.1.fc17.9-x86_64)
OpenJDK 64-Bit Server VM (build 23.0-b21, mixed mode)

How to change the Java version/enviroment in Ubuntu

If you have installed multiple Java-Versions and you want to configure your system to use one of them as the default, there is a really simple command to achieve that goal:

1) Check Java version

$ java -version

• The output should look similar to something like this:

  java version "1.7.0_147-icedtea"
  OpenJDK Runtime Environment (IcedTea7 2.0) (7~b147-2.0-0ubuntu0.11.10.1)
  OpenJDK 64-Bit Server VM (build 21.0-b17, mixed mode)
  

  As you can see my systems default is set to java-7-openjdk (1.7.0_147-icedtea).

How to get the top 10 recently used commands

The file .bash_history in a users home-directory saves the recently used commands. You can modify the maximum number of lines that will be stored in .bash_history. You only have to change the value of the global bash variable $HISTFILESIZE. For much more details have a look at the bash man-page.

We use sort, uniq and head to get the top 10 recently used command.

How to remove overscan on HDMI 1080p output using xrandr

I recently got a Asus 24T1E TV monitor with integrated DVB tuner and lots of connectors on the back, two of which are HDMI inputs. When I first connected my Laptop to it via HDMI and turned it to 1920×1080 (native resolution of the monitor) I encountered that the picture was kind of blury and the borders of the desktop were outside of the screen, i.e. 52 pixels on the left and right and 26 pixels on the top and bottom border. The info pannel on the monitor’s OSD reported “1080p” as resolution.