string[] lines = doc.Split('n');
for (int i = 0; i < lines.Length; i+= 1)
   lines[i] = lines[i].Trim();

string path = "yourfile.txt";
string[] lines = File.ReadAllLines(path);

string content = File.ReadAllText(path);
string[] lines = content.Split(
    Environment.NewLine.ToCharArray(),
    StringSplitOptions.RemoveEmptyEntries);

string line = String.Empty;
StreamReader reader = new StreamReader(path);
while ((line = reader.ReadLine()) != null)
{
    // do stuff
}

StreamReader reader = new StreamReader(file);
string _Line = reader.ReadToEnd();
string IntMediateLine = string.Empty;
IntMediateLine = _Line.Replace("entersign", "");
string[] ArrayLineSpliter = IntMediateLine.Split('any specail chaarater');

private static string[] Split(string s, string delim)
    {
        if (s == null) throw new NullReferenceException();

        // Declarations
        var strings = new ArrayList();
        var start = 0;

        // Tokenize
        if (delim != null && delim != "")
        {
            int i;
            while ((i = s.IndexOf(delim, start)) != -1)
            {
                strings.Add(s.Substring(start, i - start));
                start = i + delim.Length;
            }
        }

        // Append left over
        strings.Add(s.Substring(start));

        return (string[]) strings.ToArray(typeof(string));
    }