How to Upgrade Ubuntu Distribution?

I want to upgrade from TRUSTY to XENIAL Xerus, but Xenial will be released at April 2016. Ubuntu's Release site displays Distributions available for downlaod upto 15.10( Wily Warewolf). But we can always download the development version, but at our own risk. There might be the problem of driver and certain features which may not be ubiquitous in every hardware. 

In order to upgrade from your current distribution you can  use the Application "Software and Updates", where automatically the latest release will be available for download. In terminal type  

sudo do-release-upgrade

This will download the latest release available.But still you cannot upgrade to the development version.

So in terminal type: sudo do-release-upgrade -d

Command do-release-upgrade upgrades operating system to latest release. -d or --devel-release checks if upgrading to the latest development release is possible. 

Ever wandered about the code names given for the Ubuntu Releases? Wanna know why are they unique and sounds familiar at the same time?Checkout this Development Code where the codenames are listed in details.

Understanding Fedora, Redhat and CentOS

Talking about Linux Distribution these three are quite famous for maintaining the server and security perspectives. I don't mean to say there are only these three distributions for servers and network security, I would absolutely be wrong. In that case Slackware, Arch, Black Arch, Kali, Bodhi are some name which shouldn't be missed. I agree there are even more. But being interrelated with each other, people generally get confused about following three Linux Distributions: 

• Fedora
• Redhat
• CentOS

They get confused regarding following points:

•  Do they belong to same company?
• As Redhat is available as a commercial version do other distributions cost money as well?
• Who maintains them?
• How  often their stable versions are released?

I was also little unclear previously, so I did a little study about these three distribution and went through wikipedia. Being convinced myself I draw this diagram listing their features in order top to button.

I wish this will  somehow help.