Error in adding PPA


I am getting error in adding PPA. I want to add this PPA.
When I type
sudo add-apt-repository -s ppa:radio-astro/main
I get error

OSError: [Errno 30] Read-only file system: ‘/etc/apt/sources.list’.
How can I resolve this?


You should create /etc/apt/sources.list.d/radioastro.list and add the URL in there. Then run apt-get update