diff --git a/Cargo.toml b/Cargo.toml
index 1381623..ae779dd 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -8,7 +8,8 @@ members = [
     "hit_rate_converter",
     "cat_xlsx",
     "find_files_in_list",
-    "random_pairs_of_s3file"
+    "random_pairs_of_s3file",
+    "find_longtime_files",
     # Add other tools here
 ]
 resolver = "2"  # Add this line to specify resolver version 2
diff --git a/find_longtime_files/Cargo.toml b/find_longtime_files/Cargo.toml
new file mode 100644
index 0000000..0ddc6e9
--- /dev/null
+++ b/find_longtime_files/Cargo.toml
@@ -0,0 +1,11 @@
+[package]
+name = "find_longtime_files"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+chrono = "0.4"
+regex = "1"
+indicatif = "0.17.11"
+clap = { version = "4.5.30", features = ["derive"] }
+anyhow = "1.0.95"
diff --git a/find_longtime_files/src/main.rs b/find_longtime_files/src/main.rs
new file mode 100644
index 0000000..96e7c93
--- /dev/null
+++ b/find_longtime_files/src/main.rs
@@ -0,0 +1,127 @@
+use anyhow::{Context, Result};
+use chrono::NaiveDateTime;
+use clap::Parser;
+use indicatif::{ProgressBar, ProgressStyle};
+use regex::Regex;
+use std::fs::File;
+use std::io::{BufRead, BufReader};
+
+/// Find files with the longest processing times in a log file.
+#[derive(Parser, Debug)]
+#[command(author, version, about, long_about = None)]
+struct Args {
+    /// Number of top files to display.
+    num_files: usize,
+
+    /// Path to the log file.
+    log_file: String,
+}
+
+/// Remove ANSI escape codes from a string.
+fn remove_ansi_codes(s: &str) -> String {
+    // Regex to match ANSI escape sequences.
+    let ansi_re = Regex::new(r"\x1B\[[0-9;]*[a-zA-Z]").unwrap();
+    ansi_re.replace_all(s, "").to_string()
+}
+
+/// Extract the timestamp from a line (first two whitespace-separated tokens).
+fn extract_timestamp(line: &str) -> Option<String> {
+    let parts: Vec<&str> = line.split_whitespace().collect();
+    if parts.len() < 2 {
+        None
+    } else {
+        Some(format!("{} {}", parts[0], parts[1]))
+    }
+}
+
+/// Extract the filename from a line using a regex.
+/// Captures the filename following "The format of" and before "is <format>".
+fn extract_filename(line: &str) -> Option<String> {
+    let re = Regex::new(r"The format of\s+(\S+)\s+is\s+\S+").unwrap();
+    re.captures(line)
+        .and_then(|caps| caps.get(1).map(|m| m.as_str().to_string()))
+}
+
+fn main() -> Result<()> {
+    // Parse command-line arguments using clap.
+    let args = Args::parse();
+
+    // Open the log file.
+    let file = File::open(&args.log_file)
+        .with_context(|| format!("Error opening log file: {}", args.log_file))?;
+    let metadata = file.metadata().context("Failed to get file metadata")?;
+    let total_size = metadata.len();
+    let reader = BufReader::new(file);
+
+    // Create a progress bar based on the total file size.
+    let pb = ProgressBar::new(total_size);
+    pb.set_style(
+        ProgressStyle::default_bar()
+            .template("[{elapsed_precise}] [{bar:40.cyan/blue}] {bytes}/{total_bytes} ({eta})")
+            .unwrap()
+            .progress_chars("##-"),
+    );
+
+    // We'll store (duration_in_seconds, filename) pairs.
+    let mut diffs: Vec<(f64, String)> = Vec::new();
+
+    // Variables to hold the previous log entry's timestamp and file name.
+    let mut prev_dt: Option<NaiveDateTime> = None;
+    let mut prev_file: Option<String> = None;
+
+    // Timestamp format: milliseconds (3 digits).
+    const TIMESTAMP_FORMAT: &str = "%Y-%m-%d %H:%M:%S.%3f";
+
+    for line in reader.lines() {
+        let line = line.context("Error reading a line")?;
+        pb.inc((line.len() + 1) as u64);
+
+        // Remove ANSI escape sequences.
+        let clean_line = remove_ansi_codes(&line);
+
+        // Extract and parse the timestamp.
+        let ts_str = match extract_timestamp(&clean_line) {
+            Some(ts) => ts,
+            None => continue,
+        };
+
+        let naive_dt = match NaiveDateTime::parse_from_str(&ts_str, TIMESTAMP_FORMAT) {
+            Ok(dt) => dt,
+            Err(e) => {
+                eprintln!("Error parsing date '{}': {}", ts_str, e);
+                continue;
+            }
+        };
+
+        // Extract the filename.
+        let filename = match extract_filename(&clean_line) {
+            Some(f) => f,
+            None => continue,
+        };
+
+        // If we have a previous timestamp, compute the processing duration.
+        if let (Some(prev), Some(prev_filename)) = (prev_dt, &prev_file) {
+            let duration = naive_dt.signed_duration_since(prev);
+            let diff_seconds = duration.num_microseconds().unwrap_or(0) as f64 / 1_000_000.0;
+            diffs.push((diff_seconds, prev_filename.clone()));
+        }
+
+        prev_dt = Some(naive_dt);
+        prev_file = Some(filename);
+    }
+
+    pb.finish_with_message("Processing complete");
+
+    // Sort by processing time in descending order.
+    diffs.sort_by(|a, b| b.0.partial_cmp(&a.0).unwrap());
+
+    println!(
+        "Top {} files with longest processing times:",
+        args.num_files
+    );
+    for (i, (duration, file)) in diffs.iter().take(args.num_files).enumerate() {
+        println!("{}. {} took {:.6} seconds", i + 1, file, duration);
+    }
+
+    Ok(())
+}