Hash a file without reading it all at once.
Python: Feed fixed-size binary chunks into SHA-256 for files larger than memory.
import hashlib
digest = hashlib.sha256()
with open("data.bin", "rb") as file:
for chunk in iter(lambda: file.read(65536), b""):
digest.update(chunk)
print(digest.hexdigest())Expected output EXAMPLE
2cf24dba5fb0a30e26e83b2ac5b9e29e1b161e5c1fa7425e73043362938b9824
Details
Save as snippet.py and run python3 snippet.py. Uses the Python standard library. Feed fixed-size binary chunks into SHA-256 for files larger than memory.
A hash verifies content equality, not the identity of the sender.
Tested on Ubuntu 24.04.5 LTS · · Python 3.12.3 · python3 3.12.3-0ubuntu2.1
Test inputs, results and environment
The exact published code ran in a dedicated Linux test container with prepared inputs. Unprivileged snippet process, external networking disabled, read-only root filesystem, and a fresh temporary working directory. Fixtures and output records are isolated from the application database. Testing covers this example and its stated checks, not every input, operating system, or runtime version. The Linux container shares its host's kernel; this is not a native Windows test.
- Architecture / host kernel
- x86_64 / 6.18.54.1-microsoft-standard-WSL2
- Snippet identity / locale
- uid=65534, gid=65534 (unprivileged) / C.UTF-8
- Interpreter invocation
python3 -c <published code>- Container image ID
sha256:32dc2d998158b6554c99b73b533f423696a0f3e31e8cbea9db10b5eee9a2fadd- Code SHA-256
31a5dc9da7ea918dd404495e443ce3b79a2a83cf9a4d65617919828c2e75fa1f- Dependencies
- python3 3.12.3-0ubuntu2.1
Test input setup
These are the prepared inputs used by the test harness. See Details above for the prerequisites and how to run this example.
printf 'hello' > data.bin
Observed standard output
2cf24dba5fb0a30e26e83b2ac5b9e29e1b161e5c1fa7425e73043362938b9824
Exit code: 0. Standard error: empty. Validation: Exact stdout comparison. System-dependent values above are one recorded run.