git add - libgit2/libgit2sharp GitHub Wiki
The following examples assume you already have a repository in place to work with. If not, see git-init.
Add to a non-bare repository
If you want to stage (add) a file in a repository that is checked out to the file system, you can stage a file with changes like so:
using (var repo = new Repository(@"path/to/your/repo"))
{
// Stage the file
repo.Index.Add("file/with/changes.txt");
repo.Index.Write();
}
Stage all working directory changes
Git
$ git add --all .
LibGit2Sharp
using (var repo = new Repository(@"path/to/your/repo"))
{
Commands.Stage(repo, "*");
}