Archive for linux

Monitor Power Off

// March 14th, 2010 // No Comments » // how to, linux

Q: What do you do if you go away from your computer for a while and want to turn off the screen to prolong its life time, save energy and reduce your carbon footprint ?
A: Use a software that can turn off your your monitor with just a mouse click.

Windows
On Windows NirCmd can be used. Just create a shorcut with the following target:

"C:\Program Files\nircmd\nircmd.exe" cmdwait 1000 monitor off

Linux
Create a script with the following commands.

#! /bin/sh
if [ ! -z $1 ] ; then
if [ -z "$(echo $1 | awk '/^[0-9]+$/')" ] ; then
echo Usage: poweroff_monitor [SECONDS]
echo Example: poweroff_monitor 10
echo If SECONDS is set, it waits SECONDS seconds before it suspends the monitor.
exit
fi
sleep $1
fi
xset dpms force standby


The  script can be used either as a shortcut from your favorite graphical interface or straight from the command line.

    
                        

					
                    

					    
                    

    
                        

                            
How to install Java on RHEL 5

                            
 // March 7th, 2010 // No Comments » // how to,  linux,  rhel

                        
                        
1. Check your operating system just to be sure:


[root@andrei ~]# cat /etc/redhat-release      
Red Hat Enterprise Linux Server release 5.4 (Tikanga) 


2. Check weather it’s a 32 or 64 bit version:


[root@andrei ~]# uname -a      
Linux <output omitted> x86_64 x86_64 x86_64 GNU/Linux  


The current OS is a 64 bit system, indicated by  x86_64.


3. Download Java (JDK) – select Linux or Linux64 depending on your OS and download the required file. In my case is jdk-6u18-linux-x64-rpm.bin.


4. Make the downloaded file executable and then run it:


[root@andrei ~]# chmod u+x jdk-6u18-linux-x64-rpm.bin        
[root@andrei ~]# ./jdk-6u18-linux-x64-rpm.bin 




5. After you accept the License Agreement the installation starts. 


6. Your Linux distribution most likely comes with a Java version installed, but it is probably the GNU Compiler for Java (gij – GNU libgcj).Now you need to configure the system to use the newly installed Sun Java.


[root@andrei ~]# alternatives --install /usr/bin/java java /usr/java/jdk1.6.0_18/bin/java 2
[root@andrei ~]# alternatives --config java




After the second command you will be asked to make a selection of the Java version used in your system. Choose option number 2.


7. Check that your system has a new Java environment:




[root@andrei ~]# alternatives --display java




See what version of Java Runtime Environment you are using now:




[root@andrei ~]# java -version
java version "1.6.0_18"
Java(TM) SE Runtime Environment (build 1.6.0_18-b07)
Java HotSpot(TM) 64-Bit Server VM (build 16.0-b13, mixed mode)



    
                        

					
                    

					    
                    

    
                        

                            
GNU/Linux Advanced Administration

                            
 // February 5th, 2010 // No Comments » // linux

                        
                        
The Free Technology Academy has released a book about “GNU/Linux Advanced Administration”. The book is divided in modules, each module being focused on a part of the Linux operating system. The main subject coverd by the book is system administration and you can download it from the FTA website.


From the FTA website:


The GNU/Linux systems have reached an important level of maturity, allowing to integrate them in almost any kind of work environment, from a desktop PC to the sever facilities of a big company.


Evolution of this book


The FTA has reused existing course materials from the Universitat Oberta de Catalunya (UOC). The first version of this course book was published in 2004 for the Master Programme in Free software of the UOC. In 2008, this book was translated into English with the help of the SELF (Science, Education and Learning in Freedom) Project, supported by the European Commission’s Sixth Framework Programme. In 2009, this material has been improved by the Free Technology Academy. Additionally the FTA has developed a study guide and learning activities which are available for learners enrolled in the FTA Campus. 




The evolution of this books is interesting to me, because it has evolved from existing course materials. I think there are many books out there that have such an evolution and are designed with a specific goal in mind. 


Freshmen who are attending the course “Operating Systems Usage” at the Computer Science Department of the “Politehnica” University of Bucharest have available a similar book written by the team in charge of the course. You can find it on Google books (Romanian version only).


[FTA via cibercity.biz]