grep "fail" -i /var/log/messages |wc -l
grep "fail" -i /var/log/messages
grep "Call" -i /var/log/messages |wc -l
grep "Call" -i /var/log/messages
grep "fail" -i /var/log/messages
grep "error" -i /var/log/messages

ll -rt |less

grep "/sbin/nologin" /etc/passwd | wc -