This is a script to remove automatically all the 404 Not found PPA's.Copy the below code and paste it into a file and name it as ppa-remove.
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#!/bin/bash
sudo rm /tmp/update.txt; tput setaf 6; echo "Initializing.. Please Wait"
sudo apt-get update >> /tmp/update.txt 2>&1; awk '( /W:/ && /launchpad/ && /404/ ) { print substr($5,26) }' /tmp/update.txt > /tmp/awk.txt;...
Automated Removal of 404 Not found PPA's through script