Split Text File by Line Size - C#

Just a quick program I wrote that separates a textfile into 2 different files: the first containing all lines that have < 5,000k characters, and the second containing all lines that have 5,000k or over characters. Each of these new files goes into a created directory named "5KSplit".

Note: The first line of the file is ignored because the format I was working with in this case contains a header line.

Note 2: StreamWriter is writing in UTF-8 Encoding because the format of file I was working with is best interpreted in UTF-8 as opposed to ASCII.

I apologize for the lack of format in the following code. For some reason when I copied it over it lost all formatting.

/*
* Creator: Calvin Hawkes 7-15-10
*/



public void FiveKCharSplit(FileInfo file)
{

StreamReader sr = new StreamReader(file.FullName);
DirectoryInfo trgDir = new DirectoryInfo(file.Directory.FullName + "\\5KSplit\\");

if (!trgDir.Exists)
  trgDir.Create();

StreamWriter sw = new StreamWriter(trgDir.FullName + file.Name, true, Encoding.UTF8); //File                 with <5k char lines

string header = sr.ReadLine(); //header
sw.WriteLine(header);
string line = null;
List over5k = new List(); //lines over5k



while ((line = sr.ReadLine()) != null)
{
  if (line.Length >= 5000) //change 5000 to character number you wish to split by
  {
  over5k.Add(line);
  }
  else //if good line
  {
  sw.WriteLine(line);
  }
}

sr.Close();
sw.Flush();

//Writing lines over 5k into different file
if (over5k.Count > 0)
{
  Console.WriteLine("{0} Contains Line(s) over 5,000 Char.\n Splitting now...", file.Name);
  sw = new StreamWriter(trgDir.FullName + file.Name.Substring(0, file.Name.Length - 4) +       
  "_Over5K.txt", true, Encoding.UTF8);
  sw.WriteLine(header);

  foreach (string s in over5k)
  {
    sw.WriteLine(s);
  }
  sw.Flush();
}
sw.Close(); 
  
}