请教各位大牛，正则表达式匹配结果的筛选问题

Question

请教各位大牛，用正则表达式从配置文件里匹配IP地址“10.46.178.77”，现在需要将第一个匹配结果的IP修改为108.38.105.14，注释中的不修改。该怎么做？

        <IPvX>4</IPvX>
        <localIP>localhost</localIP>
        <seedcount>1</seedcount>
        <seedport>7000</seedport>
        <s0>10.46.178.77</s0>
        <!-- sample of 3 seeds -->
        <!-- 
        <seedcount>3</seedcount>
        <seedport>7000</seedport>
        <s0>10.46.178.77</s0>
        <s1>10.46.178.78</s1>
        <s2>10.46.178.79</s2>
        -->

Answer 1

用这样的正则表达式，会把匹配到的所有结果都修改掉，会误改不需要改的配置
ip=108.38.105.14
sed -i "s/10.46.178.77/$ip/g" $link_config_xml