Upgrade Ubuntu from one version to another.

Few simple steps:

• Go to "Software sources" change the box that "notify me when an LTS version is available" to "notify me when ANY new version is available".
• Then run your updater again, then it should come up with message "New version of Ubuntu is available".
• Click on "Upgrade button" then it will start upgrading your ubuntu. It may take several minutes, keep calm and wait for full upgrade.

Object Oriented Analysis and Design

Object Oriented Analysis and Design is the basic concept for all the developers. To understand this basic concept clearly I found Simon Allardice lecture video which is 100% efficient. First time I found this videos I viewed it twice which made my thinking clear.
I have provided the youtube link below, Does not matter you are the beginner or middle level developer it is fruit full for all, it only takes couple of hours. By investing this couple of hours you can boost your career far better.

Link: Simon Allardice Lecture

XAMPP: Couldn't start MySQL! on Ubuntu or Linux Mint, be calm :)

"Warning: World-writable config file '/opt/lampp/etc/my.cnf' is ignored
XAMPP: Couldn't start MySQL!"

first step write this command on terminal :
#chown -hR root /opt/lampp
and
#chmod 777 -R /opt/lampp
restart the lampp
#opt/lampp/lampp restart
if still show this message

Warning: World-writable config file '/opt/lampp/etc/my.cnf' is ignored
XAMPP: Couldn't start MySQL!

write this second step on terminal :
# chmod 644 /opt/lampp/etc/my.cnf
and
# /opt/lampp/lampp restart

Stopping XAMPP for Linux 1.8.1...
XAMPP: Stopping Apache with SSL...
XAMPP: XAMPP-MySQL is not running.
XAMPP: Stopping ProFTPD...
XAMPP stopped.
Starting XAMPP for Linux 1.8.1...
XAMPP: Starting Apache with SSL (and PHP5)...
XAMPP: Starting MySQL...
XAMPP: Starting ProFTPD...
XAMPP for Linux started.

Wrong Permission for phpmyadmin

If you install xampp server in linux and it shows :

Wrong permissions on configuration file, should not be world writable!

be calm:
There are three types of users in linux environment, usually we give 777 permission to folders or files which means
111(7) - Owner can read write execute
111(7) - other in the group can read write execute
111(7)  - rest of world can read write execute.
which is wrong permission for xampp
to solve this problem simply change the mode of xampp to 755
"sudo chmod 755 -R /opt/lampp/"
which means:
111(7) - Owner can read write execute
101(5) - other in the group can execute or read, no write
101(5) - rest of world can read and execute, no write.
Then restart the xampp
"sduo /opt/lampp/lampp restart"

Online Grub Install for Ubuntu

Boot your machine with the ubuntu installation media. And click on the TRY UBUNTU.
Open the terminal and follow the commands:
#sudo add-apt-repository ppa:yannubuntu/boot-repair
#sudo apt-get update
#sudo apt-get install -y boot-repair
#boot-repair
Click the required configuration of the grub and click next………..