md5-part-file by @michalbe

Calculate md5 hash of only part of the file

How to use:

npm install md5-part-file

then:

var md5pf = require('md5-part-file');

// Arguments are: filename, first byte, last byte, callback
md5pf('filename', 0, 1024, function(err, result) {
  console.log(result); // 788567c42aa94359406a8119b450d3ac
});

Thanks @mmalecki for help.