How to automatically go through and edit long txt files? - list

Question

I have an issue: I've got some chat logs that are thousands of lines ong, and I'm trying to isolate the messages from one specific user. The log looks like this:
[dd-mm-yy hh:mm pm/am] Username
message
[dd-mm-yy hh:mm pm/am] Username
message
[dd-mm-yy hh:mm pm/am] Username
message
In my file, I want to only keep the messages (not the other information like day hour or their username) that one specific user has send, and delete everything else, so I can process the contents of those messages. Is there anything out there that can help me achieve it, because as you can see its a very tedious process to go through thousands of lines of logs doing this by hand.

Answer 1

I ended up writing a js script to do what I wanted since I couldnt find anything anywhere else, here it is:
const fs = require("fs");
const readline = require("readline");
async function processLineByLine() {
const fileStream = fs.createReadStream("./input.txt");
const rl = readline.createInterface({
input: fileStream,
crlfDelay: Infinity,
});
// Note: we use the crlfDelay option to recognize all instances of CR LF
// ('\r\n') in input.txt as a single line break.
let trigger = false;
for await (const line of rl) {
// Each line in input.txt will be successively available here as `line`.
console.log(`Line from file: ${line}`);
if (line.includes("YOU DID THIS TO MY BOI LIM#7483") == true) {
console.log("true");
trigger = true;
}
else if (trigger == true) {
console.log(`Line sent by user: ${line}`);
fs.appendFile("output.txt", line + " ", (err) => {
// throws an error, you could also catch it here
if (err) throw err;
// success case, the file was saved
console.log("line saved");
});
trigger = false;
}
}
}
processLineByLine();