How to remove an apt repository that I added myself? [duplicate]

I was following an old tutorial and did an apt-get installed a repository (I think that's what it was) I am no ubuntu guru. Turns out that repo no longer exists, and when I now do an apt-get update I get this:

W: Failed to fetch http://ppa.launchpad.net/colingille/freshlight/ubuntu/dists/wily/main/binary-i386/Packages  404  Not Found

I tried the usual

sudo rm /var/lib/apt/lists/* -vf

but no luck. Where is the list that stores all the repos that i added myself? How do I get rid of this?

The command to remove an apt repository is apt-add-repository with the -r option which will remove instead of add the repository. So in your case, the full command would be:

sudo add-apt-repository -r ppa:colingille/freshlight

The other option is to look in /etc/apt/sources.list and /etc/apt/sources.list.d/ and remove it from there.