while true; do (echo "%CPU %MEM ARGS $(date)" && ps -e -o pcpu,pmem,args --sort=pcpu | cut -d" " -f1-5 | tail) >> ps.log; sleep 5; done

# log a processed cpu usage every second
while [ 1 ]
do #change 25029 to your process id to monitor top -b -n 2 -d 0.2 -p 25029 | tail -1 | awk '{print $9}' sleep 1
done