Regular Expressions
How to Use Regex in Python re Module for Scripts Easily
Use the Python re module in scripts: search, match and fullmatch, named groups, finditer, sub with a function, flags, raw strings and backtracking.
6 min read
Tag
python
30 posts
Python
How to Use asyncio to Run Shell Commands Concurrently
Run shell commands concurrently with asyncio.create_subprocess_exec: capture output, cap concurrency with a semaphore, add timeouts and kill stuck children.
6 min read
Python
How to Run Parallel Jobs in Python With concurrent futures
Run jobs in parallel with Python's concurrent.futures: threads for waiting work and commands, processes for CPU work, as_completed, errors and limits.
6 min read
Python
How to Use Python Subprocess With Timeouts and Retries
Run commands from Python with a timeout, catch TimeoutExpired and CalledProcessError, retry with backoff and kill whole process trees when a command hangs.
6 min read
Python
How to Package a Python CLI and Install It With pipx
Package a Python command line tool with pyproject.toml and a console script entry point, install it with pipx or uv tool, upgrade it and build for others.
6 min read
Python
How to Make a Python Script Executable From the Shell
Make a Python script executable: write the env python3 shebang, set the mode bit, avoid CRLF line endings, handle virtual environments and put it on PATH.
6 min read
Python
How to Write Single File Python Scripts With Dependencies
Write single file Python scripts that declare their own dependencies using PEP 723 inline metadata, run them with uv or pipx, lock versions and share them.
6 min read
Python
How to Run Python Scripts in Virtual Environments With uv
Run Python scripts in isolated environments with uv: create a venv, run with uv run, add one-off packages, pin a Python version and use it in a shebang.
6 min read
Testing
How to Test CLI Tools in Python With pytest and subprocess
Test a Python command line tool with pytest: subprocess and in-process runs, exit codes and output, tmp_path, monkeypatch and parametrized cases.
6 min read
Python
How to Handle Signals and Cleanup in Python Scripts
Handle SIGINT and SIGTERM in Python scripts: stop a loop cleanly, run cleanup with try and finally, use atexit, and know which signals cannot be caught.
6 min read
Python
How to Use the Python REPL and ipython for Terminal Work
Use the Python REPL and IPython for terminal work: history, tab completion, magics like %timeit, shell commands, editing and a useful startup file.
6 min read
Python
How to Use Python to Send Email From Scripts the Safe Way
Send email from a Python script with smtplib and EmailMessage: STARTTLS, passwords from the environment, attachments, HTML bodies and error handling.
6 min read