Linux Shell Scripting Cookbook - Third Edition

Changing scheduler priority using the nice command

Every task on a Linux system has a priority. The priority values range from -20 to 19. The lower the priority (-20), the more CPU time a task will be allocated. The default priority is 0.

Not all tasks need the same priority. An interactive application needs to respond quickly or it becomes difficult to use. A background task run via crontab only needs to finish before it is scheduled to run again.

The nice command will modify a task's priority. It can be used to invoke a task with modified priority. Raising a task's priority value will free resources for other tasks.