cat /var/log/auth.log | grep sshd
To check the zipped ones, use
zcat /var/log/auth.log.1.gz | grep sshd
useful tidbits for using open source software in science
cat /var/log/auth.log | grep sshd
To check the zipped ones, use
zcat /var/log/auth.log.1.gz | grep sshd