digup is a console tool to update md5sum or shasum digest files. It will read existing digest files, check the current directory for new, updated, modified, renamed, or deleted files, and query the user with a summary of changes. After reviewing the updates, they can be written back to the digest file. This makes digup very useful to update and verify incremental archives like chronological data storages, which are commonly stored and backed up on hard disks. Using a full file digest scan, even slowly creeping bad blocks on old hard disks can be detected. By using a crontab entry, this check can be performed unattended and routinely.
phalanx computes a digest of many buffers simultaneously, and produces a combined hash of them all. It is an initiative to provide a fast, simple, and portable alternative method to compute a checksum in a parallel fashion. It has options for I/O buffer size, hash width, number of threads, and more. It can be run single-threadedly for performance comparisons. It can check files against previously-saved sums, like "MD5sum" does. It also has a "demo" mode, to ascertain accurate operation. It is intended to be useful on large files and multicore/multiprocessor/multithreaded environments.