chkbit

chkbit generates cryptographic hashes for the files on a primary disk and stores those checksums in an index file that can be moved with the data to backup locations. By recomputing and comparing the stored hashes to the current file contents, the tool can detect whether any file has become corrupted after being copied, moved, or stored over time.

The utility is intended for users who need to verify the integrity of large collections of files, such as personal backups, archival storage, or any environment where data loss could be caused by hardware failures, software bugs, power interruptions, or other sources of bit‑level errors. It can also be used to identify duplicate files through its deduplication support, helping to reduce redundant data on backup media.

chkbit is a stable, command‑line‑only program that works by creating a single index file (or multiple files) that travels with the data, allowing verification at any later point without requiring the original source files. It provides a straightforward way to uncover hidden corruption and maintain confidence in stored information.