I need to read a big text file and search for a string in each line, each line separated by linebreak and I need to minimize I/O and RAM 

My idea is to separate the file into chunks, so I have two approachs:

1) Split the FileStream with something like this but then I risk that text lines will be cut in half and that can make things complex: 

```
 using (FileStream fsSource = new FileStream("InputFiles\\1.txt", FileMode.Open, FileAccess.Read))
            {
                // Read the source file into a byte array.
                int numBytesToRead = 1024; // Your amount to read at a time
                byte[] bytes = new byte[numBytesToRead];

                int numBytesRead = 0;
                while (numBytesToRead > 0)
                {
                    // Read may return anything from 0 to numBytesToRead.
                    int n = fsSource.Read(bytes, numBytesRead, numBytesToRead);

                    // Break when the end of the file is reached.
                    if (n == 0)
                        break;

                    //done something with the lines here.
                }
            }

```

2) Create an extension method to split the list of lines into smaller lists of lines and then search the word in each line but I am unsure about how this method can affect I/O and RAM!. 

```
public static IEnumerable<IEnumerable<TValue>> Chunk<TValue>(this IEnumerable<TValue> values, int chunkSize)
        {
            using (var enumerator = values.GetEnumerator())
            {
                while (enumerator.MoveNext())
                {
                    yield return GetChunk(enumerator, chunkSize).ToList();
                }
            }
        }

        private static IEnumerable<T> GetChunk<T>(IEnumerator<T> enumerator, int chunkSize)
        {
            do
            {
                yield return enumerator.Current;
            } while (--chunkSize > 0 && enumerator.MoveNext());
        }

```

Any thoughts or other methods I can use?

Thanks in advance.