Read data

read.js

// echo -en "\x01\x02\x03hello" > data
// node read.js data

let fs = require('fs')
let file = process.argv.slice(2)[0]
let buffer = fs.readFileSync(file)

for (let value of buffer) {
  let decimal = value
  let hex = value.toString(16)
  let ascii = String.fromCharCode(value)

  console.log(`${decimal} 0x${hex} ${ascii}`)
}

/**
  1 0x1
  2 0x2
  3 0x3
  104 0x68 h
  101 0x65 e
  108 0x6c l
  108 0x6c l
  111 0x6f o
 */