How to Tail and Colorize Error Lines in Python

import sys
import time
from pathlib import Path

def tail_colorize(filename: str, lines: int = 20) -> None:
    """Read last N lines of a file, printing errors in red."""
    path = Path(filename)
    if not path.exists():
        print(f"File '{filename}' not found.", file=sys.stderr)
        return

    # Read last N lines
    content = path.read_text(errors="replace").splitlines()
    tail_lines = content[-lines:] if lines > 0 else content

    # ANSI color codes
    RED = "\033[91m"
    RESET = "\033[0m"

    for line in tail_lines:
        if "error" in line.lower() or "ERROR" in line:
            print(f"{RED}{line}{RESET}")
        else:
            print(line)

if __name__ == "__main__":
    # Example usage: create a sample log file and colorize it
    sample_log = Path("sample_log.txt")
    sample_log.write_text(
        "INFO: Server started\n"
        "ERROR: Connection refused\n"
        "DEBUG: Retrying in 3s\n"
        "ERROR: Timeout occurred\n"
        "INFO: Shutdown complete\n"
    )
    tail_colorize(str(sample_log), lines=5)