nice - macOS

Overview

The nice command in macOS allows users to adjust the priority of a command or process, influencing how quickly the system allocates resources to it. It is commonly used to give higher or lower priority to specific tasks, ensuring a balanced resource distribution among multiple processes running concurrently.

Syntax

nice [-n increment] [-i increment] command [arguments]

Options/Flags

  • -n increment: Adjust the nice level positively by increment. Higher values (up to 19) indicate lower priority, while lower values (down to -20) indicate higher priority. The default increment is 10.
  • -i increment: Similar to -n, but adjusts the nice level inversely. Lower values indicate lower priority, while higher values indicate higher priority.

Examples

  • To run ls with a higher priority (-5):
nice -n -5 ls
  • To run sleep 10 with a lower priority (15):
nice -n 15 sleep 10
  • To increase the priority of the top process by 3:
nice -i 3 top

Common Issues

  • Permission denied: Ensure you have sufficient user privileges to adjust process priorities (sudo may be required).
  • Invalid increment: The increment must be between -20 and 19.
  • No effect: Processes with very low priority (above 19) may not experience any noticeable performance changes.

Integration

  • nice can be used in conjunction with renice, which allows for dynamic adjustment of process priorities while they are running.
  • It can be combined with ps to display the priority level of running processes. For example:
ps -e -o nice,command
  • ps – Display process information.
  • renice – Change the priority of a running process.
  • top – Monitor system performance and running processes.