Permlink is what shows up in the URL when you go to a post -- it is the permanent link to that post. In this case of this post:
author: @thescubageek
permlink: steem-api-basics-part-1-parsing-post-payloads-with-ruby

All comments also have permlinks, which are generated according to the rules as I describe in the post above. Your comment, for example, has the following parameters:
author: @augustinanweke
permlink: re-thescubageek-steem-api-basics-part-1-parsing-post-payloads-with-ruby-20180301t024812479z

The cool this is that we can also use the get_post method I wrote above to get information about individual comments (and comment trees!), not just posts.

post = SteemPostFinder.new('steem').get_post('augustinanweke','re-thescubageek-steem-api-basics-part-1-parsing-post-payloads-with-ruby-20180301t024812479z')

In an upcoming post I'll go into more detail on how the post / comment hierarchy works and how we can grab this data from the API payload.

I hope this helps @augustinanweke...