git operations on remote repository without local clone

Question

What kind of read-only operations are possible on a remote git repository using the standard git command line tool without having a local clone?

• Is there some way to list refs (in particular tags and branches) on the remote repo?
• Is there a way to list the content of a given directory in a given revision?
• Is it possible to retrieve the content of a given file at a given revision?

I guess that doing this without a local clone might involve some low level primitive operations, and I guess that making this usable might best be accomplished by some short shell script. That would still be within the scope of this question.

Answer 1

Is there some way to list refs (in particular tags and branches) on the remote repo?

Yes, that is what git ls-remote does.

Is there a way to list the content of a given directory in a given revision?
Is it possible to retrieve the content of a given file at a given revision?

2012: However, beside getting branches and tags, I don't think you can get the content without cloning (full clone or sparse checkout or shallow clone).
And you cannot do a shallow clone for a specific commit or tag, or for a specific branch.

Update 2016:

• since git 1.70 you can clone a single branch
• since git 2.5 (mid 2015), you can fetch a single commit(!) without cloning the full repo.