Okay, so I had nginx 1.4.6 running on ubuntu 13.10 without any problems.
I tried to update nginx to 1.6.0 via this url (http://leftshift.io/upgrading-nginx-to-the-latest-version-on-ubuntu-servers)
Now nginx is not running and not willing to start (no reaction at all). nginx -v gives "nginx: command not found" as a result. So looks like nginx can't be found.
I looked around here and on other sites, but wasn't able to find the solution. So, if anyone can.. plz do..