How to open a file with a specific name in Python?

You have a script, you know the exact filename you want, and you want a clean, cross-platform way to open it without surprises. A recent community thread asked for clear patterns that work reliably across Windows, macOS, and Linux, including tips for error handling, matching by pattern, and avoiding common pitfalls.

How to open a file with a specific name in Python?
I need to open a file by exact filename (sometimes by pattern), read its contents, and handle cases where the file might not exist or there are multiple matches. What is the best practice using modern Python, and how can I make this robust across platforms and CI environments?

The best approach is to use pathlib for paths and context managers for opening files. This gives you cross-platform behavior, clearer intent, and safer cleanup. Let’s dig a little deeper.

from pathlib import Path

# Exact filename in a known directory
base_dir = Path.cwd()  # or Path(__file__).parent for script-relative paths
file_name = "report.txt"
path = base_dir / file_name

# Fail fast if missing
if not path.is_file():
    raise FileNotFoundError(f"File not found: {path}")

# Safe open with context manager
with path.open("r", encoding="utf-8") as f:
    content = f.read()
print(content)Code language: PHP (php)

• Use Path.cwd() for current working directory or Path(__file__).parent for file-relative paths.
• Always specify encoding when reading text files to avoid locale-dependent bugs.

from pathlib import Path

path = Path("output/log.txt")
path.parent.mkdir(parents=True, exist_ok=True)  # ensure directory exists
# "x" fails if the file exists; "w" overwrites
with path.open("x", encoding="utf-8") as f:
    f.write("Initialized\n")Code language: PHP (php)

from pathlib import Path

with Path("image.png").open("rb") as f:
    blob = f.read()Code language: JavaScript (javascript)

from pathlib import Path

root = Path("data")
matches = sorted(root.rglob("report_*.csv"))  # recursive glob

if not matches:
    raise FileNotFoundError("No matching report_*.csv found")
if len(matches) > 1:
    # pick the newest, or apply your own selection logic
    target = max(matches, key=lambda p: p.stat().st_mtime)
else:
    target = matches[0]

with target.open("r", encoding="utf-8") as f:
    print(f"Reading {target}")
    content = f.read()Code language: PHP (php)

Windows filesystems are typically case-insensitive, while Linux and most macOS configurations are case-sensitive. If you must match case-insensitively, filter manually:

from pathlib import Path

folder = Path("inbox")
name_ci = "Invoice.PDF".casefold()
candidates = [p for p in folder.iterdir() if p.is_file() and p.name.casefold() == name_ci]

if not candidates:
    raise FileNotFoundError("invoice.pdf not found (case-insensitive search)")
path = candidates[0]Code language: JavaScript (javascript)

• Never trust unvalidated user-supplied paths. If you accept a filename, normalize with Path and consider rejecting path components like .. to avoid traversal.
• Prefer absolute paths in CI and services to avoid reliance on the working directory.
• Wrap file access in try-except for ergonomics in CLIs and servers.

from pathlib import Path

def read_text_safe(path: Path) -> str:
    try:
        return path.read_text(encoding="utf-8")
    except FileNotFoundError:
        return ""
    except PermissionError as e:
        raise RuntimeError(f"Insufficient permissions for {path}") from eCode language: JavaScript (javascript)

If your workflow involves images or videos, opening a file is often the first step before processing or uploading. For Python-centric image handling tips, see 6 ways to save images in Python.

After opening a local image or video file, many teams upload to Cloudinary to handle optimization, versioning, transformations, and delivery. Using Cloudinary’s Python SDK, a simple upload after opening a file looks like this:

import cloudinary
import cloudinary.uploader
from pathlib import Path

cloudinary.config(
    cloud_name="your_cloud",
    api_key="your_key",
    api_secret="your_secret",
    secure=True,
)

media_path = Path("assets/hero.png")
with media_path.open("rb") as f:
    res = cloudinary.uploader.upload(f, folder="assets", resource_type="image")
    print("Public URL:", res["secure_url"])
Code language: JavaScript (javascript)

Once uploaded, you can transform and deliver via simple, configurable URLs.

• Use pathlib for paths and with open for safe file handling.
• Validate existence, handle permissions, and prefer absolute paths in automation.
• Use rglob for pattern-based discovery and implement case-insensitive matching when needed.

Use pathlib to compose paths and context managers to open files. Validate the file exists, handle exceptions cleanly, and rely on globbing when names vary. For media pipelines, open locally, then optionally upload to Cloudinary for optimization and reliable delivery using URL-based transformations.

• Image to JPG
• PNG to WebP
• Compress PNG
• Image to Link

Ready to streamline your media workflows and delivery? Sign up for Cloudinary free and start optimizing today.