picca/man/algorithm.1.md

% (1) Version | User Commands % Written by Bryson Steck (bryson@steck.dev) % August 2025

NAME

sum - a Parallel Implementation of the algorithm

SYNOPSIS

sum [OPTIONS] [FILE]...

DESCRIPTION

Print or verify checksums by reading files in parallel, using the algorithm.

When conditions are suitable, being able to hash multiple files in parallel can significantly increase performance with multi-file hashing operations. However, it can also significantly degrade performance depending on different factors with your particular system. Some factors to consider are:

• The type of storage being used,
• The type of processor(s) in the system,
• The latency of I/O operations,
• etc.

sum is a standalone binary of the picca project that only runs the algorithm. See picca(1) for information on the main binary.

OPTIONS

With no FILE(s) specified, or when FILE is a dash (-), sum will read from standard input.

-c, ––check CHECK

Read checksums from the specified file and verify them. This argument can be specified multiple times to read checksums from multiple files.

-d, ––debug

Enable debug output for troubleshooting purposes. Messages output to standard error.

-f, ––canonicalize

Show canonicalized file paths; convert relative paths to absolute paths.

-h, ––help

Show command usage and available options

-t, ––threads THREADS

Use at most, at any given time, this number of threads. By default, sum will detect the amount of processors on the system and use that as the thread count. Using 0 for this value results in the default behavior; this is the same as omitting this option.

-V, ––version

Show the version of picca and exit

The following option is only useful when verifying checksums with the -c flag:

-q, ––quiet

Only print checksums that fail verification; do not print anything to standard output if a verfication is successful. Helpful to limit the amount of information printed to the screen.

REPORTING BUGS

Bugs to the picca project can be submitted via an issue on Codeberg: https://codeberg.org/bryson/picca

COPYRIGHT

Copyright © 2025 Bryson Steck.