My constant git commandline annoyance is that some commands take remote branches as `origin mybranch` and some take `origin/mybranch` .. maybe there is an arcane reason for this, but I've never seen it.
So, if we take the example from derefr [1], `git chekcout foo` lets you go to your own local branch `foo`. Then, `git reset --hard origin/foo` modifies the current local ref (`foo`) to be the same as `origin/foo`, and change the working directory accordingly.
Also git reset appears to be taking a commit as the final parameter, git reset [--soft | --mixed [-N] | --hard | --merge | --keep] [-q] [<commit>]
But why it is accepting `origin/mybranch`.
I am mostly rambling - feel free to ignore me.
That isn't a single argument, that's two arguments. If you look at docs for some commands which accept `origin mybranch`, git fetch for example, it says the first argument is `<repository>` which can either be a URL or a remote name. In your example it's a remote called `origin`. The 2nd argument is then a `<refspec>` which is a bit complex - it specifies what to fetch and where to fetch it. So in your example `mybranch` is shorthand for `mybranch:mybranch` (i.e. fetch `mybranch` from `origin` and update local `mybranch`). You can even do `git fetch origin mybranch:mybranch-local` which would fetch `mybranch` from `origin` and update `mybranch-local` with it.