This catches the loopback(::1) as well and ipv6 addresses.
changed {} to + and put : inside the first square bracket.
([a-f0-9:]+:+)+[a-f0-9]+
tested on with ifconfig -a output
http://regexr.com/
Unix or Mac OSx terminal o option returns only the matching output(ipv6) including ::1
ifconfig -a | egrep -o '([a-f0-9:]+:+)+[a-f0-9]+'
Get All IP addresses (IPv4 OR IPv6) and print match on unix OSx term
ifconfig -a | egrep -o '([0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}) | (([a-f0-9:]+:+)+[a-f0-9]+)'
