def freeze(h, output_yaml, resolve, groups):
    """Output installed packages."""
    if not groups:
        groups = filter(lambda group: not group.lower().startswith("bower"),
                        h.requirements.keys())
    else:
        groups = [text_type.strip(group) for group in groups.split(",")]

    if output_yaml:
        for requirements in h.requirements.values():
            for requirement in requirements:
                if resolve and not requirement.version:
                    requirement.load_installed_version()
        click.echo(h.requirements.yaml)
    else:
        for group in groups:
            if not h.requirements[group]:
                continue
            click.echo("# {}".format(group))
            for requirement in h.requirements[group]:
                if resolve and not requirement.version:
                    requirement.load_installed_version()
                click.echo(str(requirement))
def update(self, dest, url, rev_options):
        # type: (str, HiddenText, RevOptions) -> None
        # First fetch changes from the default remote
        if self.get_git_version() >= parse_version('1.9.0'):
            # fetch tags in addition to everything else
            self.run_command(['fetch', '-q', '--tags'], cwd=dest)
        else:
            self.run_command(['fetch', '-q'], cwd=dest)
        # Then reset to wanted revision (maybe even origin/master)
        rev_options = self.resolve_revision(dest, url, rev_options)
        cmd_args = make_command('reset', '--hard', '-q', rev_options.to_args())
        self.run_command(cmd_args, cwd=dest)
        #: update submodules
        self.update_submodules(dest)