fanctl is a replacement for fancontrol from lm_sensors meant to have a more fine-grained control interface in its config file.
fancontrol's configuration is pretty cryptic, and controlling it is quite hard. Rust was chosen as the implementation language of choice due to the problems that can arise if the program controlling your fans crashes un-cleanly (potentially causing hardware to overheat).
fancl -c <CONFIG_FILE>
An example configuration file can be found at fanctl.yml.
More detailed information can be found in the documentation. The config module is a good place to start.
Alternatively, if the online docs are out of date, or you are working on an un-released version, you can build the documentation locally with cargo.
cargo doc --no-deps
fanctl is released under the GNU General Public License v3.0.
See the COPYING file for more information.