[SQLai Lama]

Для сравнения, прочие решения.

Код:

# perl
perl -nle "print $1 if /received/ and /(\b\d{1,3}(?:\.\d{1,3}){3}\b)/" openvpn.txt

# grep
grep 'received' openvpn.txt | grep -oP '\b([0-9]{1,3}\.){3}[0-9]{1,3}\b'

# ruby
ruby -ne "puts $_.scan(/\b\d{1,3}(?:\.\d{1,3}){3}\b/) if /received/" openvpn.txt