c# search last key word .log file

Question

I am trying to search through a text /.log file for the key word "DEBUG 2018-06-04T13:27:15+00:00" Once the last key word DEBUG is found, I would then like to compare the date and time to current date $ time and if older than 10 minutes output fail.

Answer 1

You can extract all the matching substrings with Regex.Matches:

String text = File.ReadAllText(@"C:\My\File\Path.txt");

MatchCollection matches = Regex.Matches(
    text,
    @"DEBUG (\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}\+\d{2}:\d{2})"
)

Inspect the last match:

if (matches.Count > 0) {
    Match last = matches[matches.Count - 1];
    DateTime dt = DateTime.Parse(last.Groups[1].Value);

    if (DateTime.Now > dt.AddMinutes(10)) {
         Console.WriteLine("Last date entry is older than 10 minutes ago: {0}", dt);
    }
}

Or loop through all matches:

foreach (Match match in matches) {
    // Parse the date string in the matched text:
    DateTime dt = DateTime.Parse(match.Groups[1].Value);

    if (DateTime.Now > dt.AddMinutes(10)) {
        // Date is older than 10 minutes ago
        Console.WriteLine("Date is older than 10 minutes ago: {0}", dt);
    }
}