Return a list of sysctl parameters for this minion

    CLI Example:

    .. code-block:: bash

        salt '*' sysctl.show

def show(config_file=False):
    '''
    Return a list of sysctl parameters for this minion

    CLI Example:

    .. code-block:: bash

        salt '*' sysctl.show
    '''
    roots = (
        'compat',
        'debug',
        'dev',
        'hptmv',
        'hw',
        'kern',
        'machdep',
        'net',
        'p1003_1b',
        'security',
        'user',
        'vfs',
        'vm'
    )
    cmd = 'sysctl -ae'
    ret = {}
    comps = ['']

    if config_file:
        # If the file doesn't exist, return an empty list
        if not os.path.exists(config_file):
            return []

        try:
            with salt.utils.files.fopen(config_file, 'r') as f:
                for line in f.readlines():
                    l = line.strip()
                    if l != "" and not l.startswith("#"):
                        comps = line.split('=', 1)
                        ret[comps[0]] = comps[1]
            return ret
        except (OSError, IOError):
            log.error('Could not open sysctl config file')
            return None
    else:
        out = __salt__['cmd.run'](cmd, output_loglevel='trace')
        for line in out.splitlines():
            if any([line.startswith('{0}.'.format(root)) for root in roots]):
                comps = line.split('=', 1)
                ret[comps[0]] = comps[1]
            elif comps[0]:
                ret[comps[0]] += '{0}\n'.format(line)
            else:
                continue
        return ret