How to display random link on page refresh [closed]

I want to display random link from big list (in txt file) on my wp blog's sidebar on every page refresh . How to do that in PHP? List of links is big 5-10k in plain text format, line by line:

http: //domain.net
http: //domain2.org
http: //domain3.net

Link on sidebar must be clickable. How to do that, can anybody help me?