my ($nickname, $last_fingerprint) = $line =~ /
\A      # anchor at start
\#      # literal number sign
\w{3}   # month
\s
\d\d    # day
\s
\d\d:\d\d:\d\d\.\d{3}   # timestamp
\s
\[\w+\] # log level between brackets
\s
.*?     # log msg
\s
\(      # literal paren open
.*?     # stuff in the parens
\s      # space preceding the nickname
(\w+)   # capture the nickname
\)      # literal paren close
:
\s
\$[0-9A-F]{40}\(\w+\)   # literal $, 40 hex digits, paren open, word, paren close
\s
\$[0-9A-F]{40}\(\w+\)   # again
\s
\$([0-9A-F]{40})\(\w+\) # capture last fingerprint
\z      # anchor at end
/msx;   # PBP