log line number in vim whenever a line is deleted - vim

Question

I have an application that generates a txt file with thousands of lines. I have to delete some lines manually by going through the file (using vim). However, I might need to generate the same file again if a change in format is required. That will make me go through the file again to delete the same lines.
The solution to avoid deleting manually repeatedly is that vim somehow logs the line number when I delete a line. I can then use some script to remove those lines. Is it possible to get this behavior in vim?
Otherwise, is there any other editor to get this behavior? There are many lines I have to delete and it's not feasible for me to log each line number manually.

Answer 1

As suggested by phd and wxz, I was able to use git-diff of the file to extract the deleted lines by using node package gitdiff-parser for parsing the diff.
const gitDiffParser = require('gitdiff-parser')
const { exec } = require("child_process");
let p = new Promise( (res,rej) => {
exec("git diff -U0 file.txt", (error, stdout) => {
res(stdout)
});
});
p.then(s=>{
diff = gitDiffParser.parse(s);
diff[0].hunks.forEach(element => {
console.log(`start: ${element.oldStart}, end: ${element.oldStart + element.oldLines - 1}`)
});
})
Another solution or say hack was to append line number in each line of the file and extract the undeleted line numbers after removing the required lines.