Monitor number of open file handles for a process over time

gistfile1.txt

#!/bin/bash
# Provide pid of process for which you want to monitor the number of file handles
# You probably want to use it somewhat like this
# ./file_handle_mon.sh 1877 | tee file_handle_mon.out

while [ 1 ]
do
  number=$(lsof -p $1 | wc -l)
  date=$(date -u +"%Y-%m-%dT%H:%M:%SZ")
  echo "$date,$number"
  sleep 10
done