rcheck

rcheck is a command-line utility designed for checking the integrity of files. It is typically used to verify that downloaded files have not been corrupted during transfer or storage. rcheck works by comparing a file's content against a checksum, a unique digital fingerprint generated from the file's data. If the computed checksum matches the provided checksum, the file is considered intact.

The utility usually requires two pieces of information: the file to be checked and the expected checksum value. This checksum is often provided by the source of the file, typically alongside the download link. Common checksum algorithms supported by rcheck include MD5, SHA-1, and SHA-256, among others. The choice of algorithm can influence the security and reliability of the check.

Users invoke rcheck from their terminal, specifying the checksum algorithm and the file path. For example, a command might look like `rcheck sha256 filename.zip`. The program then calculates the checksum of `filename.zip` using the SHA-256 algorithm and outputs whether the calculated checksum matches a pre-defined or provided value. If the checksums do not match, it indicates that the file is likely corrupted and should be re-downloaded. rcheck is a simple yet effective tool for ensuring data integrity in various computing scenarios.