E:Type 'http://pastebin.ubuntu-gr.org/f50818e5c' is not known on line 1 in source list /etc/apt/sources.list
That is the message when I try to update. When I try to open software center its not opening!
edit the file with gedit
Comment out (add a # at the very front) or delete line 1.
Save and exit.
If you want us to review the line, post it here.