C#

using System;
using System.IO;
using System.Collections;

namespace CodeProject
{
	/// <summary>
	/// CLass that might do somethings you need?
	/// </summary>
	public class AppendAndMove
	{
		private const int LIMIT  = 10;
		private int m_LinesWritten = 0;
		private string m_File1 = @"job.txt";
		private string m_File2 = @"oldjob.txt";

		public AppendAndMove()
		{
			// get lines in m_File1 so far...
			if (File.Exists(m_File1))
			{
				using(StreamReader sr = new StreamReader(this.m_File1) )
				{
					while (sr.ReadLine() != null)
						this.m_LinesWritten++;
				}
			}
		}

		/// <summary>
		/// appends the content of file1 to file2
		/// after that file1 is deleted
		/// </summary>
		private void MoveContent()
		{
			// move content
			using(StreamWriter sw = new StreamWriter(this.m_File2,true))
			{
				using(StreamReader sr = new StreamReader(this.m_File1) )
				{
					string line = sr.ReadLine();
					while (line != null)
					{
						sw.WriteLine(line);
						line = sr.ReadLine();
					}
				}
			}
			// delete file
			File.Delete(this.m_File1);
		}

		/// <summary>
		/// add a line to the file1 file
		/// if the file contains 10 lines, move the content
		/// to file2
		/// if m_LinesWritten is zero the file will be emptied
		/// </summary>
		/// <param name="line">the line to add</param>
		public void AddLine(string line)
		{
			using(StreamWriter sw = new StreamWriter(this.m_File1,true))
			{
				sw.WriteLine(line);
				m_LinesWritten++;
			}

			// reacht the limit?
			if (m_LinesWritten == LIMIT)
			{
				MoveContent();
				// reset count of written lines in file1
				m_LinesWritten =0;
			}
		}

		private string[] FindValueInFile(string fileName,int columnIndex, string value)
		{
			ArrayList result = new ArrayList();
			if (File.Exists(fileName))
			{
				using(StreamReader sr = new StreamReader(fileName) )
				{
					string line = sr.ReadLine();
					while (line != null)
					{
						string[] columns = line.Split(',');
						// got atleast columnIndex cols?
						if (columns.Length > columnIndex)
						{
							// is the desired value in the specified column?
							if (columns[columnIndex] == value)
							{
								// Yes, add to result...
								result.Add(line);
							}
						}
						// read next line
						line = sr.ReadLine();
					}
				}
			}
			//return result
			return (string[]) result.ToArray(typeof(string));
		}

		/// <summary>
		/// finds all lines in both files that have the specified value
		/// int the specified column
		/// </summary>
		/// <param name="columnIndex">0-based index of the column</param>
		/// <param name="value">the value to search for</param>
		/// <returns></returns>
		public string[] FindValue(int columnIndex, string value)
		{
			ArrayList result = new ArrayList();
			// search file1
			result.AddRange(FindValueInFile(this.m_File1,columnIndex, value));
			// search file2
			result.AddRange(FindValueInFile(this.m_File2,columnIndex, value));

			//return result
			return (string[]) result.ToArray(typeof(string));
		}


		/// <summary>
		/// Test the class
		/// </summary>
		[STAThread]
		static void Main() 
		{
			// Application.Run(new Form1());
			AppendAndMove testClass = new AppendAndMove();
			System.Text.StringBuilder sb = new System.Text.StringBuilder();
			Random rnd = new Random();
			for(int i=0;i<100;i++)
			{
				sb.Length=0;
				for(int t = 0;t<8;t++)
				{
					sb.Append(rnd.Next(1,100));
					if (t != 7)
						sb.Append(",");
				}
				testClass.AddLine(sb.ToString());
			}

			string[] foundLines = testClass.FindValue(2,"50");
			foreach(string s in foundLines)
				System.Console.Out.WriteLine(s);

		}
	}
}

My Blog ^

<br />
// I Did this experiment with a LED<br />
SerialPort comPort = new SerialPort("COM1");<br />
comPort.Open();<br />
// This will keep electricity flowing <br />
// through the pin while the program is on<br />
for (int i=0; i<1; i=0){<br />
  comPort.Write("1"); //Any value works here<br />
}<br />
comPort.Close();<br />