Regex: Named Captures 

• A prettier regex

m{
    ^\S+                                  # Client host/IP
    \s\S+                                 # Identd user
    \s\S+                                 # HTTP auth user
    \s\[.*?\]                             # Date/timestamp
    \s"GET\s(/\S*)\s[^"]*"                # URL path requested
    \s\d+                                 # HTTP status code
    \s\d+                                 # Bytes sent in body
    \s"\Q$site_root\E(/[^"]*)"            # Referring URL path
}x;