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#!/usr/bin/env nodevar argv = require('yargs/yargs')(process.argv.slice(2))    .usage('Count the lines in a file.\nUsage: $0')    .demand('f')    .alias('f', 'file')    .describe('f', 'Load a file')    .argv;
var fs = require('fs');var s = fs.createReadStream(argv.file);
var lines = 0;s.on('data', function (buf) {    lines += buf.toString().match(/\n/g).length;});
s.on('end', function () {    console.log(lines);});