$ nice /dir/myamd.sh

$ nice -n 15 sm WILLY WILLIAM - Ego.m4a &> /dev/null &
[1] 29426
$ ps -lp $!
F S   UID   PID  PPID  C PRI  NI ADDR SZ WCHAN  TTY          TIME CMD
0 S  1000 29426  2279  1  95  15 - 141822 poll_s pts/7   00:00:00 sm

cpulimit -l 25 /dir/myamd.sh