'use strict';

const fs = require('fs');

const path = require('path');

const S = require('sanctuary');

const main = () => {

const dir = process.argv[2];

let index;

try {

index = fs.readFileSync(path.join(dir, 'index.txt'), {encoding: 'utf8'});

} catch (err) {

process.stderr.write(String(err) + '\n');

process.exit(1);

}

const readFile = filename => {

try {

return fs.readFileSync(path.join(dir, filename), {encoding: 'utf8'});

} catch (err) {

process.stderr.write(String(err) + '\n');

process.exit(1);

}

};

process.stdout.write(S.lines(index).map(readFile).join(''));

};

if (process.mainModule.filename === __filename) main();