check if a file is text based on its content

detectTextFile.js

// detect if a text file, like Perl's stat(file); if(-T) ...
fs.open(file,'r',function(err, fd){
	if(err) return;
	var len = 100;
	var buf = new Buffer(len);
	var re = /[.a-z0-9(){}\[\]? "':;<>?\s\n\r\t "':;#@~$%*<>.,_=+-]/ig;
	fs.read(fd,buf,0,len,0,function(err,num,buf){
		if(err || num < 1) return;
		var str = buf.toString('utf-8',0,num);
		// do we have enough of the types of characters typical of a text file?
		var charCount = (str.match(re) || []).length;
		if(charCount/num > 0.6){
		// probably a text file
		fs.readFile(file,'utf8',function(err,data){
			if(err) return;
			var results = data.match(options.search);
			if(results){
				console.log('found in (', (charCount/num), ')',file,results.length);
				console.log(results);
			};
		});
		};
	fs.close(fd);
	});
});