Sort IP address

Sorting IP addresses using sort is not easy because the dot confuses sort.
This line makes it possible to sort by the whole value of the address

sort -n -t . -k 1,1 -k 2,2 -k 3,3 -k 4,4 ipaddresses.txt

You can also sort by the last octet

sort -r. -n +3.0 ipaddresses.txt