Is there an "unofficial" software center with all the PPAs?

If you have lots of PPAs, you may want to try a graphical "PPA Manager" to make life easier. Scroll down directly to the PPA Manager section for a recommendation.

No, there is no unofficial "PPA" software center for Ubuntu.

One of Ubuntu's primary goals is to be a stable and reliable desktop Linux for the masses. That is why the packages (and specific versions) in the Software Center/official repositories are carefully vetted and checked for stability. The official repositories (with partners, etc.) should be sufficient for the needs of most regular users.

Why? : Software from a PPA should not be blindly installed

In theory, adding even one PPA package, no matter how "trusted" the source, has the potential to break Ubuntu such that it would be beyond the capability of the average user to fix it.

Thus, installing software from a PPA has to be a conscious and considered choice:

• What am I installing?
• Why I am installing it?
• How is it going to affect my system?

Most of the answers of the type you mention -- "add this repository and install" -- WILL address these concerns for the questioner/user; those that don't are quickly edited/downvoted/commented on.

The three-step add-update-install-from-PPA process makes it more likely people will think a little about what they are doing

The "pain" of adding individual PPAs is somewhat like the "pain" of having to use sudo instead of just being root all the time. Compared to a one-click install of unofficial packages, the terminal-based three-step process increases the chances that the user has given some thought to what he or she is doing.

Updating PPAs can take longer, because they are not mirrored

I agree that updating PPAs often takes longer for many users, because they are hosted only on launchpad.net and not mirrored. Hopefully Canonical is aware of this and is considering some kind of solution. Note that there is no intrinsic (software/design-wise) reason PPAs should take longer to update than any other repository - they have the same structure.

You can always use a PPA manager to make life easier - try Y-PPA Manager!

Managing PPAs from the command-line can become tiring; if you have three or more PPAs, I recommend you consider the Y-PPA Manager utility. You must install it from a PPA (naturally! :-), and is available as:

• y-ppa-manager in ppa:webupd8team/y-ppa-manager
• It lets you search PPAs for a particular package (via Launchpad)
• And other management functions such adding, deleting, purging, etc.

Some screenshots to give you an idea:

1. Main Window:

   

2. Searching all PPAs for "vlc":

   

3. Listing all packages in a PPA:

   

For a true user-contributed "Software Center", try Arch Linux

• Other distributions which have different goals than Ubuntu and are targeted towards users more comfortable/skilled with Linux do have what you want.
• e.g. Arch Linux has a one-stop "unofficial Software Center" - it's called "Arch User Repositories" (AUR)
• Any user can contribute a package, any other user can install it (after building from source), and the community can vote on packages as a sign of trust/helpfulness. Popular, high-voted packages can even make it into their official repositories.

In addition to being inadvisable, creating a repository to provide all software in all PPA's is also impossible.

It is common for different PPA's to provide their own special versions of the same software, with the same ppa version numbers. Even if you somehow managed to install all PPA's, you would have no idea what exactly you'd be installing. This would be bad even if all PPA's provided good software that could be trusted.

While installing all PPA's at once would be a bad situation, it is at least theoretically possible. However, a single repository cannot provide more than one different package with the same name and version, at the same time. So for a single repository to do this is not possible.

Imaginably, all software from all (public) PPA's could be downloaded and repackaged with different version numbers, incorporating the name of the PPA into the version number. Then a single repository could provide all this software. If this were done, then you'd have to enter the PPA name every time you wanted to install something or query information about it. This would be even more work than is currently required for enabling a PPA, because you only have to enable a PPA once (or a few times, if it's disabled manually or automatically during a release upgrade, and you want to keep using it).

For a curated list with many PPA's, you can try Ubuntu Tweak. It has the list available within the application.

Another option is to try the ppa offerings from the webupd8.org website . They update these sources fairly regularly.