grep - Grepping logs for IP addresses

Question

I am quite bad at using "basic?" unix commands and this question puts my knowledge even more to test. What I would like to do is grep all IP adresses from a log (e.g. access.log from apache) and count how often they occur. Can I do that with one command or do I need to write a script for that?

Answer 1

You'll need a short pipeline at least.

sed -e 's/([0-9]+.[0-9]+.[0-9]+.[0-9]+).*$/1/' -e t -e d access.log | sort | uniq -c

Which will print each IP (will only work with ipv4 though), sorted prefixed with the count.

I tested it with apache2's access.log (it's configurable though, so you'll need to check), and it worked for me. It assumes the IP-address is the first thing on each line.

The sed collects the IP-addresses (actually it looks for 4 sets of digits, with periods in between), and replaces the entire line with it. -e t continues to the next line if it managed to do a substitution, -e d deletes the line (if there was no IP address on it). sort sorts.. :) And uniq -c counts instances of consecutive identical lines (which, since we've sorted them, corresponds to the total count).