Weapon Swaying: HL2 style

I was wondering if somebody could make something like this:

Never mind the weapons, I just want the swaying part. And the crowbar hit recoil. Thanks in advance.

In other words the Single player hl2 Look sway, The stuff that gets removed in MP Source Games?

Hehehe I found another video linked with that one:

I’m not quite sure how to do this, but you could just put in custom running animations for your models. It looks pretty awesome.
E.g. this: