# Write the top of most-CPU-using and most-RAM-using processes to the log every 5 minites:
3,8,13,18,23,28,33,38,43,48,53,58  *   *  *  *  root  date +"\%d \%b" >> /var/log/CPU.log; top -b | head -20 >> /var/log/CPU.log ; echo >> /var/log/CPU.log
# Rotate log every fourth day:
11  1   */4  *  *  root  mv /var/log/CPU.log /var/log/1.CPU.log