ます-stem + な

[Javizy]

I keep seeing this, and it seems to be some sort of mild imperative or way of making a suggestion, but I don't know where it stands in comparison to other similar structures. Can anyone explain in a bit more detail? Here are a few of the examples that I've seen:

無理だ。諦めな。
自分で勝手にやりな。
おいしいんだ。食べなよ。

[QuackingShoe]

Yes, it's a shortening of the なさい　suffix. I'll assume you already know what that means, so, it's just a colloquial version of that.

Of course, this shouldn't be confused with plain present + na which forms a negative imperative.

All of this is 'as far as I am aware'

[WalterWills]

I think that's correct. Take a look at this page:
http://www.jgram.org/pages/viewOne.php?tagE=na-3

[Javizy]

Thanks, that cleared it up.