How to prioritize and deprioritize specific processes

You can influence process performance by using nice values. Nice values assign a priority to cpu resources for process

Nice values range from -20 to 19

Normal users can set priorities from 0 to 19

the root can set priorities from -20 to 19

To change priorities look at lines labelled PR and NI to change a nice value press r

can also use the nice for new processes or renice for existing ones

example

 renice -n -15 2155 

the -15 is new nice value (need to be root to set it this low)

the 2155 is the process ID

to start a process with a particular priority use nice

 nice -n nice_value command 

you can check nice and CPU usage also with

 ps -o pid,pcpu,nice,comm $(pgrep sha1sum) 

note shaisum is the name of the process being checked here