How does awk '{print $1}' /var/log/nginx/access.log transform the access log?
awk '{print $1}' /var/log/nginx/access.log
It prints the first whitespace-delimited field from each line, which is the client IP in this log format.
It extracts the HTTP status code from every line.
It prints only the first complete log line.
It counts all requests from each IP automatically.