Count lines with length >= than in a file

count-lines.js

// node count-lines.js "somefile.txt" 12
var fs = require('fs')
  , length = process.argv.pop()
  , filename = process.argv.pop()

  , stream
  , counter = 0;

stream = fs.createReadStream(filename);

stream.on('data', function(lines){
  if(!lines)
    return;

  lines = lines.toString().split('\n');
  for(var key in lines){
    if(lines[key].length >= length)
      counter++;
  }
  delete lines;
});

stream.on('end', function(){
  console.log('Lines with length %s -> %s', length, counter);
});