12.04 - name of a ppa for ppa-purge

I know that exists the same question, but I think that in that question there isn't the answer. I have to purge some ppas, and I'm trying to use ppa-purge with this command:

sudo ppa-purge ppa:/ppa

But what is the ppa_name?? I have this (bad) sources.list.d

danielrichter2007-grub-customizer-precise.list       google-chrome.list.save                      n-muench-vlc-precise.list                 videolan-stable-daily-precise.list.save
danielrichter2007-grub-customizer-precise.list.save  jockey.list                                  n-muench-vlc-precise.list.save            webupd8team-unstable-precise.list
dropbox.list                                         jockey.list.save                             relan-exfat-precise.list                  webupd8team-unstable-precise.list.save
dropbox.list.save                                    langdalepl-gvfs-mtp-precise.list             relan-exfat-precise.list.save             wine-wine-builds-precise.list
freefilesync-ffs-precise.list                        langdalepl-gvfs-mtp-precise.list.save        thefanclub-grive-tools-precise.list       wine-wine-builds-precise.list.save
freefilesync-ffs-precise.list.save                   lubuntu-dev-lubuntu-daily-precise.list       thefanclub-grive-tools-precise.list.save
google-chrome.list                                   lubuntu-dev-lubuntu-daily-precise.list.save  videolan-stable-daily-precise.list

But I don't know the name, for example:

sudo ppa-purge ppa:lubuntu/ppa
Updating packages lists
PPA to be removed: lubuntu ppa
Warning:  Could not find package list for PPA: lubuntu ppa

Edit

/etc/apt/sources.list.d$ grep ppa /etc/apt/sources.list /etc/apt/sources.list.d/*

/etc/apt/sources.list:deb http://ppa.launchpad.net/tualatrix/ppa/ubuntu precise main
/etc/apt/sources.list:deb-src http://ppa.launchpad.net/tualatrix/ppa/ubuntu precise main
/etc/apt/sources.list.d/danielrichter2007-grub-customizer-precise.list:# deb http://ppa.launchpad.net/danielrichter2007/grub-customizer/ubuntu precise main
/etc/apt/sources.list.d/danielrichter2007-grub-customizer-precise.list:# deb-src http://ppa.launchpad.net/danielrichter2007/grub-customizer/ubuntu precise main
/etc/apt/sources.list.d/danielrichter2007-grub-customizer-precise.list.save:# deb http://ppa.launchpad.net/danielrichter2007/grub-customizer/ubuntu precise main
/etc/apt/sources.list.d/danielrichter2007-grub-customizer-precise.list.save:# deb-src http://ppa.launchpad.net/danielrichter2007/grub-customizer/ubuntu precise main
/etc/apt/sources.list.d/freefilesync-ffs-precise.list:deb http://ppa.launchpad.net/freefilesync/ffs/ubuntu precise main
/etc/apt/sources.list.d/freefilesync-ffs-precise.list:deb-src http://ppa.launchpad.net/freefilesync/ffs/ubuntu precise main
/etc/apt/sources.list.d/freefilesync-ffs-precise.list.save:deb http://ppa.launchpad.net/freefilesync/ffs/ubuntu precise main
/etc/apt/sources.list.d/freefilesync-ffs-precise.list.save:deb-src http://ppa.launchpad.net/freefilesync/ffs/ubuntu precise main

/etc/apt/sources.list.d/langdalepl-gvfs-mtp-precise.list:deb http://ppa.launchpad.net/langdalepl/gvfs-mtp/ubuntu precise main
/etc/apt/sources.list.d/langdalepl-gvfs-mtp-precise.list:deb-src http://ppa.launchpad.net/langdalepl/gvfs-mtp/ubuntu precise main
/etc/apt/sources.list.d/langdalepl-gvfs-mtp-precise.list.save:deb http://ppa.launchpad.net/langdalepl/gvfs-mtp/ubuntu precise main
/etc/apt/sources.list.d/langdalepl-gvfs-mtp-precise.list.save:deb-src http://ppa.launchpad.net/langdalepl/gvfs-mtp/ubuntu precise main
/etc/apt/sources.list.d/lubuntu-dev-lubuntu-daily-precise.list.save:deb-src http://ppa.launchpad.net/lubuntu-dev/lubuntu-daily/ubuntu precise main
/etc/apt/sources.list.d/n-muench-vlc-precise.list:deb http://ppa.launchpad.net/n-muench/vlc/ubuntu precise main
/etc/apt/sources.list.d/n-muench-vlc-precise.list:deb-src http://ppa.launchpad.net/n-muench/vlc/ubuntu precise main
/etc/apt/sources.list.d/n-muench-vlc-precise.list.save:deb http://ppa.launchpad.net/n-muench/vlc/ubuntu precise main
/etc/apt/sources.list.d/n-muench-vlc-precise.list.save:deb-src http://ppa.launchpad.net/n-muench/vlc/ubuntu precise main
/etc/apt/sources.list.d/relan-exfat-precise.list:# deb http://ppa.launchpad.net/relan/exfat/ubuntu precise main

/etc/apt/sources.list.d/relan-exfat-precise.list:# deb-src http://ppa.launchpad.net/relan/exfat/ubuntu precise main
/etc/apt/sources.list.d/relan-exfat-precise.list.save:# deb http://ppa.launchpad.net/relan/exfat/ubuntu precise main
/etc/apt/sources.list.d/relan-exfat-precise.list.save:# deb-src http://ppa.launchpad.net/relan/exfat/ubuntu precise main
/etc/apt/sources.list.d/thefanclub-grive-tools-precise.list:# deb http://ppa.launchpad.net/thefanclub/grive-tools/ubuntu precise main
/etc/apt/sources.list.d/thefanclub-grive-tools-precise.list:# deb-src http://ppa.launchpad.net/thefanclub/grive-tools/ubuntu precise main
/etc/apt/sources.list.d/thefanclub-grive-tools-precise.list.save:# deb http://ppa.launchpad.net/thefanclub/grive-tools/ubuntu precise main
/etc/apt/sources.list.d/thefanclub-grive-tools-precise.list.save:# deb-src http://ppa.launchpad.net/thefanclub/grive-tools/ubuntu precise main
/etc/apt/sources.list.d/videolan-stable-daily-precise.list:deb http://ppa.launchpad.net/videolan/stable-daily/ubuntu precise main
/etc/apt/sources.list.d/videolan-stable-daily-precise.list:deb-src http://ppa.launchpad.net/videolan/stable-daily/ubuntu precise main
/etc/apt/sources.list.d/videolan-stable-daily-precise.list.save:deb http://ppa.launchpad.net/videolan/stable-daily/ubuntu precise main

/etc/apt/sources.list.d/videolan-stable-daily-precise.list.save:deb-src http://ppa.launchpad.net/videolan/stable-daily/ubuntu precise main
/etc/apt/sources.list.d/webupd8team-unstable-precise.list:deb http://ppa.launchpad.net/webupd8team/unstable/ubuntu precise main
/etc/apt/sources.list.d/webupd8team-unstable-precise.list:deb-src http://ppa.launchpad.net/webupd8team/unstable/ubuntu precise main
/etc/apt/sources.list.d/webupd8team-unstable-precise.list.save:deb http://ppa.launchpad.net/webupd8team/unstable/ubuntu precise main
/etc/apt/sources.list.d/webupd8team-unstable-precise.list.save:deb-src http://ppa.launchpad.net/webupd8team/unstable/ubuntu precise main
/etc/apt/sources.list.d/wine-wine-builds-precise.list:deb http://ppa.launchpad.net/wine/wine-builds/ubuntu precise main
/etc/apt/sources.list.d/wine-wine-builds-precise.list:deb-src http://ppa.launchpad.net/wine/wine-builds/ubuntu precise main
/etc/apt/sources.list.d/wine-wine-builds-precise.list.save:deb http://ppa.launchpad.net/wine/wine-builds/ubuntu precise main
/etc/apt/sources.list.d/wine-wine-builds-precise.list.save:deb-src http://ppa.launchpad.net/wine/wine-builds/ubuntu precise main

You need to look into the list files.

For instance, I have a java ppa. The list is webupd8team-java-trusty.list.

It contains:

deb http://ppa.launchpad.net/webupd8team/java/ubuntu trusty main
# deb-src http://ppa.launchpad.net/webupd8team/java/ubuntu trusty main

So the ppa-purge command will look this way:

sudo ppa-purge ppa:webupd8team/java

For your "lubuntu" ppa the command is:

sudo ppa-purge ppa:lubuntu-dev/lubuntu-daily

The is after http://ppa.launchpad.net/ and before the distro name.

If you still get errors, then your list is damaged. You can always add a PPA then purge it, e.g.:

sudo add-apt-repository ppa:lubuntu-dev/lubuntu-daily
sudo apt-get update
sudo ppa-purge ppa:lubuntu-dev/lubuntu-daily