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

ps aux|awk  '{print $2,$3,$4}'|grep PID

where the first column is the PID,second column CPU usage ,third column memory usage.