如何使用正则表达式替换子字符串值？

Question

例如，我在一个文件中有几行，每行都是一个字符串，如下所示：

{"a":"53124647,44398061,44398058","b":"hello","c":"ha"}
{"b":"99","a":"44398049,44398031,44398028,10007072315,9569405558,10007072318","c":"ha"}
...

如果每一行被视为json对象，则每行中键"a"的值的长度是灵活的，因此如何使用sed和regular expression来替换这一对密钥"a"及其值"a":"10"？

Answer 1

$ echo '{"a":"53124647,44398061,44398058","b":"hello","c":"ha"}
{"b":"99","a":"44398049,44398031,44398028,10007072315,9569405558,10007072318","c":"ha"}' | sed 's/"a":"[^"]*"/"a":"10"/g'
{"a":"10","b":"hello","c":"ha"}
{"b":"99","a":"10","c":"ha"}

Answer 2

$ echo '{"a":"53124647,44398061,44398058","b":"hello","c":"ha"}' | sed 's@"a":"[^"]*"@"a":"10"@'
{"a":"10","b":"hello","c":"ha"}