add message if rsync already running

rsync_backup_template.sh

#!/usr/bin/env bash

#--------
# ALL dirs must end with a backslash
#--------

now=$(date +%Y-%m-%d_%H:%M:%S_%N)
src='/home/shaun/'
dest_url='127.0.0.1'
dest_dir='/home/shaun/rsync_backups/'
dest_username='shaun'

src_dirs=(
  Downloads/
  Desktop/
)

[[ $(ps aux | grep [r]sync) ]] && {
  echo "rsync already running.  Exiting..."
} || { #only run if rsync process not already running
  for dir in "${src_dirs[@]}"; do
    /usr/bin/rsync -avzP "${src}${dir}" "${dest_username}@${dest_url}:${dest_dir}" &>"/var/log/backups_${now}" 
  done
}