paginate.js

'use strict';
/******************************************************************************/
const path = process.argv[2];
let   linesPerPage = Number(process.argv[3]);
if (!path || !linesPerPage) {
  console.log('Add the file path and lines per page number, please.');
  process.exit();
}
linesPerPage -= 2;
/******************************************************************************/
const fs = require('fs');
const S = require('string');

const encoding = 'utf8'; //ascii utf8 utf16le

const rl = require('readline').createInterface({
  input: fs.createReadStream(path, encoding),
  terminal: false,
  historySize: 0
});

const outfile =  fs.openSync(path.replace(/(\.[^.]+)?$/, '.paginated$1'), 'w');

let   lines = 0;
let   page  = 0;
/******************************************************************************/
rl.on('line', line => {
	fs.writeSync(outfile, `${line}\n`, null, encoding);
  lines++;
  if (lines === linesPerPage) {
    fs.writeSync(outfile,
                  `\n${S(++page).pad(80).s.trimRight()}\n`, null, encoding);
    lines = 0;
  }
}).on('close', () => {
  if (lines !== 0) {
    fs.writeSync(outfile,
      `${'\n'.repeat(linesPerPage - lines + 1)}${S(++page).pad(80).s.trimRight()}`,
      null, encoding);
  }
});
/******************************************************************************/