solution without using wc:
var i;
var count = 0;
require('fs').createReadStream(process.argv[2])
.on('data', function(chunk) {
for (i=0; i < chunk.length; ++i)
if (chunk[i] == 10) count++;
})
.on('end', function() {
console.log(count);
});
it’s slower, but not that much you might expect – 0.6s for 140M+ file including node.js loading & startup time
>time node countlines.js video.mp4
619643
real 0m0.614s
user 0m0.489s
sys 0m0.132s
>time wc -l video.mp4
619643 video.mp4
real 0m0.133s
user 0m0.108s
sys 0m0.024s
>wc -c video.mp4
144681406 video.mp4