案例一:查看用户创建记录
# cat /var/log/messages | grep -e /usr/sbin/useradd | grep ' ID='
案例二:查看用户删除记录
# cat /var/log/messages | grep -e /usr/sbin/userdel | grep ' ID='
# cat /var/log/messages | grep -e /usr/sbin/useradd | grep ' ID='
# cat /var/log/messages | grep -e /usr/sbin/userdel | grep ' ID='