Hands On Node File System Exercise #3

gistfile1.js

var fs = require('fs');

function readBytes(filename, position) {
	fs.open(filename, 'r', function(err, fd) {
		if (err) {
			console.log(err.message);
			return;
		}

		var readBuffer = new Buffer(5);
		var bufferOffset = 0;
		var bufferLength = readBuffer.length; 
		var filePosition = position;

		fs.read(fd, readBuffer, bufferOffset, bufferLength, filePosition, function(err, readBytes) {
			if (err) {
				throw err;
			}

			if (readBytes > 0) {
				console.log('read one');
				console.log(readBuffer.slice(0, readBytes).toString());
			}
		});
	});
}

readBytes('./a.txt', 5);
readBytes('./a.txt', 10);