In the process of reinstalling Ubuntu 10.04, it came time to install my software sources (i.e., repositories). To start off, I visited my most recent post on that. It told a tale of difficulty in getting my list of "repos" to work, and referred me to one of my earlier posts.
I decided to start by simply copying the finalized list of repos that I had developed and posted in that earlier note. This replaced my existing /etc/apt/sources.list. I wasn't sure if I needed to reboot, but having done all those updates and such, I decided it couldn't hurt. On reboot, I went into System > Administration > Software Sources to see what we had. There were some items on the list that had to do with individual programs. I found another such list that was even longer. I wasn't sure why I needed repositories for individual programs; I was under the impression that repositories were places where you could get a variety of programs. So rather than add to the list (and increase the number of repositories that might report problems later on, as I had experienced previously), I pared down the list. My final list, preserved in a backup copy of /etc/apt/sources.list, was as follows:
http://archive.canonical.com/ubuntu lucid partner
http://archive.canonical.com/ubuntu lucid partner (Source Code)
http://archive.getdeb.net/ubuntu lucid-getdeb apps
http://packages.medibuntu.org/ lucid free non-free
http://ppa.launchpad.net/tualatrix/ubuntu lucid main
http://ppa.launchpad.net/ubuntu-wine/ppa/ubuntu lucid main
http://ppa.launchpad.net/ubuntu-x-swat/x-updates/ubuntu lucid main
I clicked Close. It gave me a chance to Reload, which I took. It said this:
Could not download all repository indexesI closed out of that and typed "sudo gedit /etc/apt/sources.list." Sources.list still had some lines for repositories that I had deleted, so I deleted those surplus lines. It also had commands I should run in connection with the rest, so I copied those lines into a separate file in gedit, saved it as RunForRepositories, made it executable ("sudo chmod +x RunForRepositories"), saved a copy for future use, and then ran it ("sh RunForRepositories). I went back into Software Sources, changed one thing, closed, reloaded, and got the "Could not download all repository indexes" error again. At this point, I rediscovered that you could add repositories via System > Administration > Synaptic Package Manager. In Synaptic, I went to Settings > Repositories. But this turned out to be the same thing as the Software Sources tool. In Software Sources > Other Software, I unclicked and then reclicked an item to trigger the Close > Reload option. Once again, I got the "Could not download all repository indexes" error. The first item on the list was the Medibuntu repository, with this message: "The following signatures could not be verified because the public key is not available." Following advice, I closed out of that, went into Synaptic, searched for medibuntu-keyring, and applied that. In Synaptic, I went again into Settings > Repositories and retriggered the Reload. But it didn't work -- no Reload option -- so I did it via System > Administration > Software Sources. This time the Medibuntu error was gone, and the first error in the list had to do with the Ubuntu CD. I decided I didn't want the Ubuntu CD to be a source, so in Software Sources I unchecked the CD on the Ubuntu Software tab, and then retriggered the Reload option again. No more errors.
The repository may no longer be available or could not be contacted because of network problems ...
For some reason, /etc/apt/sources.list did not show some of these changes. Maybe I had it open in a separate window while I ws going through my paces. So I edited it manually to reflect my current preference and resaved a copy on a separate partition. Now that this was done, I ran System > Administration > Update Manager and installed the new updates they had for me there. I clicked Check to repeat that step. It said my system was up-to-date. I concluded that the repository step was done.