renice : How to use renice command in Linux with examples

# nice -n 19 sleep 30

# ps axo pid,comm,nice |grep sleep
25106 sleep             0
25158 sleep            19
#

# renice -n 18  25158
25158 (process ID) old priority 19, new priority 18
#

# ps axo pid,comm,nice |grep sleep
25106 sleep             0
25158 sleep            18
#