C#

string[] lines = File.ReadAllLines(@"C:\Text.txt");

string lastLine = lines[lines.Length - 1];

string bitYouWant = lastLine.Substring(25, 9);

Console.WriteLine(bitYouWant);

Regex r = new Regex(
   @"^CREATE from S\.\d\.\d\.\d{3} to (?<value>S\.\d\.\d\.\d{3}).*$"
);
string value = r.Match(lastLine).Groups["value"].Value;
// Here value will get S.1.1.004

while (!(success = Try()));

string line3a = File.ReadAllLines( "xxx" )
   .Skip( 2 )
   .FirstOrDefault();

string line3b = File.ReadAllLines( "xxx" )
   .SkipWhile( s => s.Contains( "S.1.1.004" ) == false )
   .FirstOrDefault();

   if ( line3a != null ) {
      // etc.
   }

Quote:

The ReadLines and ReadAllLines methods differ as follows: When you use ReadLines, you can start enumerating the collection of strings before the whole collection is returned; when you use ReadAllLines, you must wait for the whole array of strings be returned before you can access the array. Therefore, when you are working with very large files, ReadLines can be more efficient.