file-hasher_skill

Overview

This skill calculates cryptographic hashes (MD5, SHA-1, SHA-256, SHA-512) for files to support integrity checks, duplicate detection, and checksum generation. It is designed for quick command-style use and scripted workflows. Results can be used to verify downloads, compare versions, or build reproducible validation steps.

How this skill works

The tool reads files in streaming mode and computes one or more hash digests without loading entire files into memory. It supports single-file hashing, multiple algorithms, batch processing (wildcards), verification against a provided hash, and duplicate discovery within a directory. Output is presented as plain checksum strings paired with filenames to make integration and parsing straightforward.

When to use it

• Verify download integrity after transfer or mirror updates
• Detect duplicate files across directories to reclaim space
• Generate checksums for release artifacts or distribution packages
• Automate integrity checks in CI/CD pipelines or nightly scans
• Quickly compare local copies of large files without re-downloading

Best practices

• Prefer SHA-256 or SHA-512 for security-sensitive integrity checks; use MD5/SHA-1 only for non-security duplicate detection
• Stream files from disk or network mounts to avoid high memory use on large files
• Store computed checksums alongside artifacts (e.g., .sha256 files) and sign them when distributing
• Use the verify mode in automated scripts to fail builds on mismatch
• When finding duplicates, confirm by file size and timestamps before deleting to avoid false positives

Example use cases

• Compute SHA-256 for a release tarball before publishing to ensure clients can verify downloads
• Run batch hashing (*.iso) to index checksums for backup archives
• Verify a downloaded package against a known SHA-512 fingerprint before installation
• Scan a media folder to find duplicate video files and generate a cleanup plan
• Integrate a verify step in CI to compare build outputs with stored checksums