There are several Bash one-liners that I’ve been shown by the talented Linux admins I’ve had the pleasure of working with over the years. This one will take something you’re interested in, say IPs from a log file, and print them in a sorted list. For example, say I wanted to see the bots trying to access SSH. The /var/log/auth.log (Debian) prints lines like the following: 2023-09-04T06:58:01.540076+00:00 HOST sshd[249345]: Invalid user blank from 1.1.1.1 port 20082 First, we need to get...
