Random Musings

The nice command in Linux is used to start a process with a specified priority. The priority range is from -20 (highest priority) to 19 (lowest priority). The default priority is 0.

• High value (e.g., 19): The process is given lower priority, allowing other processes to have more CPU time.
• Low value (e.g., -20): The process is given higher priority and gets more CPU time.

The renice command is used to change the priority of an already running process. It takes a PID and the new priority value as arguments.

Here are examples for the nice and renice commands:

1. Using nice to start a process with lower priority:

   nice -n 10 command_name

This starts command_name with a priority of 10, meaning it will run with lower priority.

2. Using nice to start a process with higher priority:

   nice -n -10 command_name

This starts command_name with a priority of -10, giving it higher priority.

3. Using renice to change the priority of an existing process (PID 1234):

   renice -n 5 -p 1234

This increases the priority of the process with PID 1234, lowering its CPU time allocation.

4. Using renice to increase the priority (higher value means more CPU time):

   renice -n -5 -p 1234

This gives the process with PID 1234 higher priority (less nice).