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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def update():
 """Update to the latest pages."""

    repo_directory = get_config()['repo_directory']
    os.chdir(repo_directory)
    click.echo("Check for updates...")

    local = subprocess.check_output('git rev-parse master'.split()).strip()
    remote = subprocess.check_output(
        'git ls-remote https://github.com/tldr-pages/tldr/ HEAD'.split()
    ).split()[0]
    if local != remote:
        click.echo("Updating...")
        subprocess.check_call('git checkout master'.split())
        subprocess.check_call('git pull --rebase'.split())
        build_index()
        click.echo("Update to the latest and rebuild the index.")
    else:
        click.echo("No need for updates.")