Automation & scripting
CLI tools, scheduled jobs, filesystem tasks, and glue scripts that save time.
Detect Circular Imports Across Python Projects Automatically
This script walks through all .py files in a directory, builds an import graph, and uses depth-first search to find cycles—printing each circular dependency chain.
import ast
import sys
from pathlib import Path
from collections import defaultdict, deque
def find_imports(filepath):
"""Return set of module names imported by a Python file."""
imports = set()
try:
with open(filepath) as f:
tree = ast.parse(f.read())
except (SyntaxError, UnicodeDe…Detect and Remove Blurry Images in Python with OpenCV
Automatically scan a directory of images, detect blur using Laplacian variance, and remove blurry images with a dry-run option for safety.
from pathlib import Path
import cv2
import numpy as np
def is_blurry(image_path, threshold=100.0):
"""
Detect if an image is blurry using Laplacian variance.
Returns True if blurry, False otherwise.
"""
img = cv2.imread(str(image_path), cv2.IMREAD_GRAYSCALE)
if img is None:
return True…Extract Every Open Graph and Social Media Meta Tag from Web Pages in Python
A Python script that fetches a webpage and extracts all Open Graph, Twitter Card, Facebook, and Article meta tags using the standard library HTML parser.
from html.parser import HTMLParser
import re
from urllib.request import urlopen
from urllib.parse import urlparse
class MetaExtractor(HTMLParser):
def __init__(self):
super().__init__()
self.meta_tags = []
def handle_starttag(self, tag, attrs):
if tag == 'meta':
attrs_…Find Best Meeting Time Across Time Zones in Python
This code calculates overlapping available hours among participants in different time zones and returns the best meeting time in UTC and each participant's local time.
from datetime import datetime, timedelta, timezone
from zoneinfo import ZoneInfo
from dataclasses import dataclass
from typing import List, Tuple, Optional
@dataclass
class Participant:
name: str
timezone: str
# weekdays availability: 0=Mon, start_hour (0-23), end_hour (0-23)
available_slots: List[Tup…How to Create a Mock Headless Browser Screenshot Stub in Python
This code provides a deterministic stub that simulates capturing webpage screenshots with a headless browser, returning formatted output without real browser dependencies.
import subprocess
import sys
def mock_screenshot_webpage(url: str, width: int = 1280, height: int = 800) -> str:
"""Stub that simulates taking a screenshot of a webpage using headless browser."""
# In real implementation, you would use playwright/selenium/headless chrome
result = {
"url": url,
…How to Download a List of URLs to a Directory in Python
This script downloads a list of URLs into a specified directory, creating the folder if needed and keeping original filenames.
import urllib.request
from pathlib import Path
def download_urls(url_list, directory):
"""Download each URL in url_list into directory, keeping original filenames."""
save_dir = Path(directory)
save_dir.mkdir(parents=True, exist_ok=True)
for url in url_list:
filename = url.rstrip('/').spl…How to Generate Project Statistics Including Lines of Code and Complexity in Python
Walk through a Python script that scans a project directory for Python files, counts lines of code excluding blanks and comments, and estimates cyclomatic complexity by counting decision keywords.
import os
from pathlib import Path
def count_lines_of_code(filepath):
"""Counts lines of code in a Python file, excluding blank lines and comments."""
try:
with open(filepath, 'r') as f:
lines = f.readlines()
code_lines = [line for line in lines if line.strip() and not line.strip()…How to Generate an Inventory CSV of Installed pip Packages in Python
This script uses subprocess and csv to list all installed pip packages and write their names and versions into a CSV inventory file.
import subprocess
import csv
def get_installed_packages():
"""Return a list of (name, version) tuples for installed pip packages."""
result = subprocess.run(
["pip", "list", "--format=freeze"],
capture_output=True,
text=True,
check=True
)
packages = []
for line in r…How to Implement a Weighted DNS Resolver with Failover in Python
Simulates a weighted DNS load balancer that distributes traffic across IPs by weight and automatically fails over when a server is marked unhealthy.
import random
import time
class WeightedDNSResolver:
def __init__(self, records):
self.records = records # list of (ip, weight)
self.total_weight = sum(weight for _, weight in records)
self.failed_ips = set()
def resolve(self):
available = [(ip, weight) for ip, weight in self…How to Quarantine Suspicious Files in Python
Move files with suspicious extensions to a quarantine folder using pathlib and shutil for safe isolation.
import shutil
import os
from pathlib import Path
def quarantine_files(source_dir, quarantine_dir, suspicious_extensions):
"""
Move files with suspicious extensions to a quarantine folder.
Returns list of moved files.
"""
source_path = Path(source_dir)
quarantine_path = Path(quarantine_dir)
…How to Write an IP Block List to hosts.deny in Python
This Python script validates a list of IP addresses and CIDR ranges, then writes them to a hosts.deny file to block connections at the TCP wrapper level.
from ipaddress import ip_network
def write_hosts_deny(ip_list, output_file="hosts.deny"):
with open(output_file, "w") as f:
for ip in ip_list:
try:
ip_network(ip)
f.write(f"ALL: {ip}\n")
except ValueError:
continue
print(f"Written…Pin Python package versions in requirements.txt
Pin package versions in requirements.txt-style text by adding ==version when no specifier is present, while preserving existing version constraints and comments.
import re
from pathlib import Path
def pin_versions(requirements_text: str) -> str:
"""
Pin package versions in requirements.txt-style text.
Adds ==version if no version specifier is present.
Keeps existing specifiers (>=, <=, ~=, etc.) unchanged.
"""
lines = requirements_text.strip().splitli…Python: Archive Old Logs by Compressing Gzip by Age
A Python script that finds .log files older than a specified age and compresses them into .gz archives while removing the originals.
import gzip
import os
import shutil
from pathlib import Path
def archive_logs(log_dir: str, max_age_days: int) -> list[str]:
"""Compress log files older than max_age_days into .gz archives.
Returns a list of compressed file paths.
"""
cutoff = time.time() - max_age_days * 86400
compressed = …Scrape HTML Tables in Python with html.parser
Extract data from HTML tables using Python's built-in html.parser module, without third-party dependencies, by overriding callback methods to track table, row, and cell states.
import html.parser
from urllib.request import urlopen
class TableParser(html.parser.HTMLParser):
def __init__(self):
super().__init__()
self.in_table = False
self.in_row = False
self.in_cell = False
self.current_cell = []
self.rows = []
self.row = []
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Automation & scripting — Python code examples
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