grep takes multiple arguments so if you want fewer processes then: grep -v -e Disconnected -e cron:session -e "invalid user" /var/log/auth.log would also su

grep takes multiple arguments so if you want fewer processes then: grep -v -e Disconnected -e cron:session -e "invalid user" /var/log/auth.log would also suffice (or you can use -E which would enable the usual "Disconnected|invalid|cron").