sudo ifconfig | head -n 2 | tail -n 1 | tr -s " " | tr " " ":" | cut -d":" -f 4

/sbin/ifconfig $(/sbin/route -n |
                 awk '$1 == "0.0.0.0" {print $8}') |
awk 'match($0, /inet addr:[.0-9]+/) {print substr($0, RSTART+10, RLENGTH-10)}'

/sbin/ip addr show eth0 | awk -F"[ /]+" '/inet / {print $3}'

ipadm show-addr net0/v4 | awk -F"[ /]+" '/ok/ {print $5}'

ipconfig getifaddr en0

ifconfig eth0 | awk -F"[ :]+" '/inet / {print $4}'

getent hosts "$(hostname)" | awk '{ print $1 }'

ip route get 1.2.3.4

74.125.139.102 via 192.168.0.1 dev wlan0  src 192.168.0.24
    cache

ip route get 1.2.3.4 | grep -oP '(?<=src )S+'

ip route get "$(ip route show to 0/0 | grep -oP '(?<=via )S+')"

ip route get "$(ip route show to 0/0 | grep -oP '(?<=via )S+')" | grep -oP '(?<=src )S+'