`punch`: set zeroes in random locations to simulate file corruption

punch

#!/usr/bin/env node

// Usage: punch <inputfile> [number of holes]

const fs = require("fs")
const process = require("process")

const file = process.argv[2]
const times = process.argv[3] || 1
const stat = fs.statSync(file)

function randomInt(min, max) {
  min = Math.ceil(min)
  max = Math.floor(max)
  return Math.floor(Math.random() * (max - min)) + min
}

const buf = fs.readFileSync(file)
const len = buf.byteLength
console.log(file + " is " + len + " bytes.")
const start = len > 1024 ? 1024 : 10

for (let i = 0; i < times; i++) {
  const loc = randomInt(start, len) // don't overwrite the header
  console.log("Punching at " + loc)
  buf[loc] = 0
}

fs.writeFileSync(file, buf)

console.log("punched!")