Nodejs从日志文件中提取所有ipAddress

Question

There is a log file generated in my application.need to read the file and extract all the ip address from the file. The programming language i am using is Nodejs. the code is like below. Not sure what i am doing wrong.

const fs = require("fs");

fs.readFile("sample.log", null, (err, data) => {
  if (err) {
    console.log("Error reading the file");
  } else {
    const fileData = data.toString();
    const ipRegex = /^((25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$/gm;
    var arr = fileData.match(ipRegex);
    console.log(arr);
  }
});

when the log file is like below it works fine

10.55.20.116
10.55.20.184
10.55.20.187
10.55.20.45
10.55.20.7

But when the input is like below it is throwing null.

tcp.0: [1609172718.597749195, {"HOSTNAME":"sample-audi-lbs-1","IP":"10.55.17.231"}]
tcp.0: [1609172718.597749195, {"HOSTNAME":"sample-audi-lbs-1","IP":"10.55.17.232"}]
tcp.0: [1609172718.597749195, {"HOSTNAME":"sample-audi-lbs-1","IP":"10.55.17.233"}]
tcp.0: [1609172718.597749195, {"HOSTNAME":"sample-audi-lbs-1","IP":"10.55.17.234"}]
tcp.0: [1609172718.597749195, {"HOSTNAME":"sample-audi-lbs-1","IP":"10.55.17.235"}]

Answer 1

The ^ means beginning of line and the $ means end of line. If your entire line is just the IP address, it'll work, but if you need to be able to pluck the IP out of any part of the line, remove both of those characters. Working below:

 const fileData = ` tcp.0: [1609172718.597749195, {"HOSTNAME":"sample-audi-lbs-1","IP":"10.55.17.231"}] tcp.0: [1609172718.597749195, {"HOSTNAME":"sample-audi-lbs-1","IP":"10.55.17.232"}] tcp.0: [1609172718.597749195, {"HOSTNAME":"sample-audi-lbs-1","IP":"10.55.17.233"}] tcp.0: [1609172718.597749195, {"HOSTNAME":"sample-audi-lbs-1","IP":"10.55.17.234"}] tcp.0: [1609172718.597749195, {"HOSTNAME":"sample-audi-lbs-1","IP":"10.55.17.235"}]`; const ipRegex = /((25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)/gm; var arr = fileData.match(ipRegex); console.log(arr);