Change priority of all processes that belong to a process group

Alters the scheduling priority/niceness of one or more running processes.
Niceness values range from -20 (most favorable to the process) to 19 (least favorable to the process).
More information: <https://manned.org/renice>.
Trick copyright: tl;dr; <https://github.com/tldr-pages/tldr>

renice -n {{niceness_value}} --pgrp {{process_group}}

click the source code to copy install renice on any operating system with command-not-found.com