Finding Top 10 Load taking processes

ps -eo pcpu,pid,user,args | sort -k 1 -r | head -10

Finding and deleting old files

find . -mtime +7 -print     #   for files older than 7 days.

find . -mtime +7 -exec /bin/rm -rf {} \; 2>/dev/null 1>&2     #   to remove files

find /var/log -mtime +60 -type f -exec rm -rf {} \;      #  for removing files from /var/log which is older than 60 days