Eco-friendly alternatives

Bazaar121
TheSimplyNatural
ShunyaAlternatives
thealternative.in
Greentechlife

Useful websites

25 Lifehack websites

101 Useful websites

e-Learning related websites (MOOC or similar)

Coursera
Khan Academy
Udacity
edX
Academic Earth
Duo Lingo - Learn languages
MIT Open Courseware
codecademy - coding languages
Learn Street - coding languages
Udemy - Coding, Design etc

New Think Tank - Excellent collection of video tutorials for Java, OOPS, Algorithms, UML etc

MOOC List - A collection of MOOC (Massive Open Online Course) -
piazza - Learning University collaboration -
Cosmo Learning - Online Videos -
Learn Now Online - Online Videos for Developer, Manager etc (MS .Net, Java, PMP, MS Office etc)

tar destination directory

tar by default extract's to the current directory, if that needs to be changed, it can be done by using below -

[rakesh@host2] tar zxvf source.tar -C /your/dest/dir/to/extract

Graphic display in Linux

In Oracle Linux Virtual Box VM, by default the graphic output is disabled. Login as root (su) and edit the file /etc/inittab as shown below

Subsequently from the command prompt run startx to start the graphic display.

It's possible that despite the above changes, errors like below may occur

[bea@vin2 Desktop]$ java -jar wls1036_generic.jar 
Xlib: connection to ":0.0" refused by server
Xlib: Invalid MIT-MAGIC-COOKIE-1 key
Unable to instantiate GUI, defaulting to console mode.

Solution:

Login as root and copy and override the .Xauthority from root's home folder to the user's home folder. As a precaution, take a backup of the user's .Xauthority file.

You can check if the graphic display is working or not by running xclock