Ubuntu non-spanned version upgrade policy guide

1. First use the fastest mirror source for you

sudo apt update
sudo apt upgrade-d
sudo apt dist-upgrade-d

Until it's done.

2. Change to official source

sudo apt update
sudo apt upgrade-d
sudo apt dist-upgrade-d

Until all is complete without prompting for any errors

Again

sudo apt upgrade
sudo apt dist-upgrade

Note: The parameter-D means that the upgrade is only downloaded and not installed, and can only be downloaded in the new state.
And so the full download and then perform the upgrade, the reason is that a lot of mirroring synchronization has time difference, in this time lag, anything can happen.

This approach is safe and effective for upgrades that are not spread across versions, which is like this: you're using Ubuntu 6.10 to always use a 6.10 source.
But if you want to upgrade from 6.10 to 7.04, be sure to look at the official documentation and follow the official instructions, and it's best to back up and then upgrade across versions.

Reloading the system is not necessary, but there is some value in upgrading it in the following way, provided that most of the software you install is installed from the Ubuntu source in apt or new Ted.

If you're using an old 6.06, it's going to be a hassle to upgrade directly to 7.04 because, according to Ubuntu, only 6.10 can be upgraded to 7.04, and 6.10 to 7.04 should be upgraded in strict accordance with the official upgrade instructions.

So 6.06 is upgraded to 7.04 via APT, which can only be upgraded to 6.10 before upgrading to 7.04. It's too expensive to be worth it.

Mr. Dogfox has a related article, but recently Dogfox seems to have disappeared, so Mr. Dogfox did not update.

I have mentioned on various occasions that overloading the system or upgrading with Dselect is very convenient. Indeed, it is possible that many people have misunderstood my meaning, because dselect may be garbled in Chinese, in fact, the effect is similar. Dselect I mean:

Apt Dselect-upgrade

So for the old Ubuntu, upgrade to the future Ubuntu ideas are as follows:

The following methods in my success, I DIY a live CD installed a lot of software, is the use of the "dselect" once done.

1. Backup the entire original system to at least keep filesystem

2. Get the original old system of the installed software list, after the implementation of this list file (Installed-software.log) back up without sudo

dpkg--get-selections > Installed-software.log

3. New Installation of Ubuntu x.04 (x.10) or 7.10 or future Ubuntu, after loading to change the source, offline upgrade source or use DVD source.

4. The new system to import the original old system installation software list:

sudo dpkg--set-selections < Installed-software.log

5. Dselect Install the software in the list of software that you just imported:

sudo apt dselect-upgrade

can also

sudo dselect

Press I (install), there is interactive interface on the selection of Yes, the system automatically installed, finished Q exit!
If your dselect is garbled, then simply read e:

Export Lang=en_us. UTF-8

This step will install all the software in the list (the source will be installed, not automatically skipped, note that some of the list file with version number or name have changed, such as Gaim-->pidgin bery--->compiz, so it may not be installed automatically, to manually install), The source does not have the software of course to install manually, in short, you can guarantee that most software will be done at once.