small JS that finds and replaces tabs with a comma and renames the file to csv from asc.

asc2csv.js

var fs = require('fs');

var filePath = process.argv[2];
console.log(filePath);

fs.readFile(filePath, function (err, data) {
  if (err) {
    return console.log(err);
  }
  var newFilePath = filePath.replace(/asc/g, 'csv');
  var result = data.toString().replace(/\t/g, ', ');
  fs.writeFile(newFilePath, result, 'utf8', function(err) {
    if (err) return console.log(err);
  })
})