Ubuntu – How to find all of the software sources

The method to backup your sources list has already been described by garbagecollector (also note the additional directory as explained by Javier Rivera).

To backup the trusted keys added to your system you can use the apt-key command line program. I don't know if there is a way to do this from the GUI.

From a terminal you can run something like this:

sudo apt-key exportall > ~/repositories.key

Then on your other system you should be able to import that key file from Software Sources or you can use apt-key again:

sudo apt-key add /path/to/repositories.key

I only have one Ubuntu desktop system so I haven't tested this out, but I think it should work.

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.