replace-numbers.js

import { readFileStr, writeFileStr } from 'https://deno.land/std/fs/mod.ts'

const ext = `.${Deno.args[0] || 'txt'}`.replace(/^\.\.+/, '.')
const filenames = (await Deno.readdir('.'))
  .map(file => file.name)
  .filter(name => name.endsWith(ext))
  .filter(name => !name.endsWith(`-replaced${ext}`))

const work = filenames.map(async name => {
  const text = await readFileStr(name)
  const replaced = text.replace(/\n\d+,\n\d+,/g, '')
  const count = (text.match(/\n\d+,\n\d+,/g)||[]).length
  if (text === replaced) return
  const newName = `${name.slice(0, ext.length)}-replaced${ext}`
  await writeFileStr(newName, replaced)
  return { name, newName, count }
})

const result = (await Promise.all(work))
  .filter(Boolean)

const totalOccurences = result
  .reduce((total, {count}) => total + count, 0)

console.log(totalOccurences, 'occurences replaced in', result.length, 'files.')

deno --allow-read=. --allow-write=. "https://gist.githubusercontent.com/kigiri/9feaa033fb35f83f22bbc7c37d7750e7/raw/cece52a9dc86ebd8a480584ffd9fc7fa88312185/replace-numbers.js"