C# Remove first line of text if it's empty and or replace first line with another string if first line contain string

Question

I tried to do some research and could not find a solution for this.

Here is my simple text:

save[0] = 0

generate_num[0] = 1

1. My expectation is to check the first line, if it's blank then remove the first line so the save[0] = [num] now should be in first line.
   save[0] = 0 generate_num[0] = 1
2. Next, I need to replace any int after the equal sign '=' for the first line only. Because the int is random, we cannot tell if it'll always be 0. I do not want to replace the string from other lines, but the first only. Ex: save[0] = 25 generate_num[0] = 1

The reason the integer for save[0] is not constant because when you close the program after you save it; it loses its place of how many times the text file has been saved.

Starting codes:

        //delete first line if empty
        string[] Reread = File.ReadAllLines(path);

        int gogetnum = Convert.ToInt32(numbers) + 2; //This will determine my next number for the random save integer.

Answer 1

Check an approach:

string text = @"  
  
save[0] = 0  
      
generate_num[0] = 1  
";  
  
string result = Regex.Replace( text, @"(?<=^\s*.+?=\s*)(\d+)", "25" );  

To increase the found number:

string result = Regex.Replace( text, @"(?<=^\s*.+?=\s*)(\d+)", m => ( int.Parse( m.Value ) + 2 ).ToString( ) );  

To read and write the file, use File.ReadAllText and File.WriteAllText.