func Quiet(args ...string) bool { cmd := gitCmd(args...) return cmd.Success() }
func IsGitDir(dir string) bool { cmd := cmd.New("git") cmd.WithArgs("--git-dir="+dir, "rev-parse", "--git-dir") return cmd.Success() }
func (r *Range) IsAncestor() bool { cmd := gitCmd("merge-base", "--is-ancestor", r.A, r.B) return cmd.Success() }