Unix:Renice Command: Change priority of already running process

"Renice"  is the command that is used to change the priority of already running process.

Options:

-u : Change priority of processes of a user

-p : Changing priority of a process with its pid . It is the default option

Example:

$ renice 15 process_id

It will change the priority of this process to 15

$sudo renice 10 -u user_name

It will change the priority of all the process of given user

Note:

1) Users other than the super-user may only alter the priority of processes they own,and can only increase their  nice value within the range 0 to 20.

2) The super-user may alter the priority of any process and set the priority to any value in the range (-20) to (19)

3) Any negative value of priority makes process execution very fast.