checksum_skill

Overview

This skill is a cross-platform CLI utility for generating and verifying cryptographic file checksums (md5, sha1, sha256, sha512). It can hash single files or recursively walk directories, and emit human-readable or JSON output for automation. Use it to confirm downloads, detect file changes, and produce integrity manifests for releases.

How this skill works

The tool reads files stream-wise and computes the requested digest using standard crypto algorithms, defaulting to md5. It can recurse directories to produce a list of path+checksum entries and optionally write JSON for machine consumption. A verification mode compares files against a checksum list to detect mismatches and missing files.

When to use it

• Validate downloaded archives or binaries before installation
• Create integrity manifests for release artifacts or backups
• Detect accidental or malicious changes in project files
• Produce JSON-formatted checksums for CI/CD pipelines
• Run periodic integrity checks on backup directories

Best practices

• Pin the algorithm you use (sha256 or sha512 recommended for stronger integrity) rather than relying on defaults
• Generate checksums on a trusted machine and distribute the manifest separately from the files
• Commit checksum manifests for release assets to make verification repeatable
• Use JSON output when integrating with automation or monitoring systems
• Run recursive hashing in off-peak times on large trees to avoid I/O contention

Example use cases

• Generate a sha256 checksum for a single downloaded package before installation
• Create a recursive checksum manifest of a release directory and publish alongside release tarballs
• Pipe JSON output into CI to verify artifacts produced by different build agents
• Run a scheduled verification job that compares current files to a stored checksum list and reports changes
• Produce checksum lists for backup archives to later confirm restore integrity