Possible Duplicate:
Is it possible to skip releases during an upgrade?
I'm using 10.04 as only OS on my 32-Bit PC (Not dual boot). Can I upgrade to 11.04 using ubuntu-11.04-desktop-i386.iso file without burning on CD or installing on USB drives. I don't have internet connection, so I cannot download alternate version too. Any help is appreciated.
UNDER NO CIRCUMSTANCES SHOULD YOU UPGRADE DIRECT TO 11.04 FROM 10.04
Despite the appearances, you should never upgrade to 11.04 without missing out 10.10, even with the desktop or alternate CDs.
See this AU answer for more details -
In summary, it is not supported, you will likely cause major issues with your install, or even break it so that it will not boot.
If you want to use the desktop CD, backup your non-hidden /home folder files and do a fresh install. After that, copy back your /home folder files.
I should point out now that I have no experience with upgrading in this manner, and that the following is what I would do if I were going to do it myself for the first time.
You can do this by adding the ISO to APT's list of repositories, documentation for which can be found here.
First you need to mount the ISO so APT can find it. Open a terminal and move into the directory in which the ISO is currently sitting. Let's say it's currently in your Downloads folder, you would type
cd ~/Downloads
Once you're there, you need to create a directory into which to mount it. Type
mkdir upgrade
to create a directory called 'upgrade' in the current directory. Now you can mount the ISO into your upgrade directory by typing
mount -o loop -t iso9660 ubuntu-11.04-desktop-i386.iso ~/Downloads/upgrade
You may need to precede the above command with sudo - I'm not sure how permissions will work if you try mounting it in a user-owned directory. Now you just need to add this upgrade directory, and with it your upgrade ISO, to APT's sources list.
sudo apt-cdrom add
sudo apt-cdrom ident
sudo apt-cdrom -d "upgrade" -r
From here, it's just a simple case of running
sudo apt-get update
sudo apt-get upgrade
and APT will pull the new packages out of the mounted ISO. Once the upgrade is complete, you can delete the upgrade directory as it is no longer needed.
Mount the iso file
Note: You cannot skip versions when upgrading AU-answer
But to install ubuntu from ISO file follow this:
Creat a mount directory called cd-image on your home directory.
Then
sudo mount ~/Desktop/ubuntu-11.04-desktop-i386.iso ~/cd-image -o loop
After that the upgrade dialog should pop up.
