Retrieve CPU usage and memory usage of a single process on Linux?

Question

I want to get the CPU and memory usage of a single process on Linux - I know the PID. Hopefully, I can get it every second and write it to a CSV using the \'watch\' command

Answer 1

Based on @caf's answer, this working nicely for me.

Calculate average for given PID:

measure.sh

times=100
total=0
for i in $(seq 1 $times)
do
   OUTPUT=$(top -b -n 1 -d 0.1 -p $1 | tail -1 | awk '{print $9}')
   echo -n "$i time: ${OUTPUT}"\\r
   total=`echo "$total + $OUTPUT" | bc -l`
done
#echo "Average: $total / $times" | bc

average=`echo "scale=2; $total / $times" | bc`
echo "Average: $average"

Usage:

# send PID as argument
sh measure.sh 3282