Reference library

Files & data

Read and write files safely; parse JSON, CSV, and common text formats.

3 matches
Files & data medium

How to Atomically Write Files in Python with Temp File and Rename

Write a file atomically using a temporary file and os.replace so readers never see partial writes even if the process crashes mid-write.

atomic-write tempfile fsync
Python
import os
import tempfile
from pathlib import Path

def atomic_write(path: str | Path, content: str) -> None:
    """Write content to path atomically using a temp file and rename."""
    path = Path(path)
    path.parent.mkdir(parents=True, exist_ok=True)

    fd, temp_path = tempfile.mkstemp(
        dir=str(path.par…
17 0 Open
Files & data medium

How to Sync Two Folders in Python (Lightweight Backup)

A Python script that synchronizes a source folder to a destination folder, copying new or updated files and removing files that no longer exist in the source.

sync backup filesystem
Python
import os
import shutil
import sys
from pathlib import Path

def sync_folders(src: Path, dst: Path):
    """Sync src folder to dst folder, copying missing/updated files."""
    dst.mkdir(parents=True, exist_ok=True)

    for src_path in src.rglob("*"):
        relative = src_path.relative_to(src)
        dst_path = ds…
38 0 Open
Files & data easy

Sync only changed files between two folders in Python

This code compares two folders and copies only the new or modified files from source to destination, skipping unchanged ones by comparing SHA-256 hashes.

files sync hashing
Python
import hashlib
from pathlib import Path
import shutil

def file_hash(path: Path, chunk_size: int = 8192) -> str:
    hasher = hashlib.sha256()
    with path.open("rb") as f:
        for chunk in iter(lambda: f.read(chunk_size), b""):
            hasher.update(chunk)
    return hasher.hexdigest()

def sync_files(src: s…
16 0 Open

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