Updating the repository isn't working

When I run sudo apt-get update get this output:

sudo apt-get update
E: Type '<!DOCTYPE' is not known on line 1 in source list /etc/apt/sources.list.d/playonlinux.list
E: The list of sources could not be read.

Also Ubuntu software Center is not opening.

Solution 1:

You seem to have saved an HTML page as a source list. The instructions for PlayOnLinux on trusty, from the website, are:

wget -q "http://deb.playonlinux.com/public.gpg" -O- | sudo apt-key add -
sudo wget http://deb.playonlinux.com/playonlinux_trusty.list -O /etc/apt/sources.list.d/playonlinux.list
sudo apt-get update
sudo apt-get install playonlinux

To check that there's no problems with the internet connection, before executing the above commands, you can do:

wget http://deb.playonlinux.com/playonlinux_trusty.list -O -

This should give:

deb http://deb.playonlinux.com/ trusty main

as the output.