I ran these commands:
sudo wget "http://pastebin.com/raw/uzhrtg5M" -O/extras/Source-list
sudo apt-get update
But it seems that I have replaced my Source-list with a Source-list of wrong version, since I am using Ubuntu 14.04 LTS but the source from which I downloaded was for Ubuntu 12.02 LTS.
The first command in your question would save a file to /extras/Source-list which would likely error out, doing nothing. But even if it did manage to save, it would almost certainly not be read by Apt (unless you really butchered your configuration).
If that is what you ran, no have no issue.
However, if the question is a typo and you actually wrote:
... -O /etc/apt/sources.list
That's more significant. If that's the case, I'd fix it by restoring the default, the proper way.
/extras/Source-listis not a path thatapt-getuses to determine package repositories to use. – David Foerster Mar 25 '16 at 12:51