picca/man/algorithm.1.md

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% <ALG>(1) Version <VERSION> | User Commands
% Written by Bryson Steck (bryson@steck.dev)
% August 2025
# NAME
<ALGORITHM>sum - a Parallel Implementation of the <ALGORITHM> algorithm
# SYNOPSIS
<ALGORITHM>sum [_OPTIONS_] [_FILE_]...
# DESCRIPTION
Print or verify checksums by reading files in parallel, using the <ALGORITHM> 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.
<ALGORITHM>sum is a standalone binary of the picca project that only runs the <ALGORITHM> algorithm. See **picca**(1) for information on the main binary.
# OPTIONS
With no FILE(s) specified, or when FILE is a dash (-), <ALGORITHM>sum will read from standard input.
**-c, &ndash;&ndash;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, &ndash;&ndash;debug**
: Enable debug output for troubleshooting purposes. Messages output to standard error.
**-f, &ndash;&ndash;canonicalize**
: Show canonicalized file paths; convert relative paths to absolute paths.
**-h, &ndash;&ndash;help**
: Show command usage and available options
**-t, &ndash;&ndash;threads** _THREADS_
: Use at most, at any given time, this number of threads. By default, <ALGORITHM>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, &ndash;&ndash;version**
: Show the version of picca and exit
The following option is only useful when verifying checksums with the **-c** flag:
**-q, &ndash;&ndash;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
# SEE ALSO
The main repository is located at https://codeberg.org/bryson/picca.
A read-only mirror is available at https://forge.steck.dev/bryson/picca.
Container images for use with Docker are available at https://forge.steck.dev/bryson/-/packages/container/picca.
# COPYRIGHT
Copyright &copy; 2025 Bryson Steck.
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>.