How to count lines fast?

Question

I tried unxutils' wc -l but it crashed for 1GB files. I tried this C# code

long count = 0; using (StreamReader r = new StreamReader(f)) {     string line;     while ((line = r.ReadLine()) != null)     {         count++;     } }  return count; 

It reads a 500MB file in 4 seconds

var size = 256; var bytes = new byte[size]; var count = 0; byte query = Convert.ToByte('\n'); using (var stream = File.OpenRead(file)) {     int many;     do     {         many = stream.Read(bytes, 0, size);         count += bytes.Where(a => a == query).Count();                         } while (many == size); } 

Reads in 10 seconds

var count = 0; int query = (int)Convert.ToByte('\n'); using (var stream = File.OpenRead(file)) {     int current;     do     {         current = stream.ReadByte();         if (current == query)         {             count++;             continue;         }     } while (current!= -1); } 

Takes 7 seconds

Is anything faster I haven't tried yet?

Answer 1

File.ReadLines was introduced in .NET 4.0

var count = File.ReadLines(file).Count(); 

works in 4 seconds, the same time as the first code snippet