const fs = require('fs'); const readline = require('readline'); const readFile = () => { // create readline interface and output to a new file; can't figure out how to write to same file const readInterface = readline.createInterface({ input: fs.createReadStream(findup('sonar-project.properties')), output: fs.createWriteStream('sonar-project.properties.temp'), console: false }); // read line by line and modify a line and rewrite it back readInterface.on('line', function(line) { if (line.includes('projectVersion')) { this.output.write('sonar.projectVersion=2020.1.0\n'); } else { this.output.write(`${line}\n`); } }); };