just gimme the IP address already

ipaddress

#!/bin/bash
#
# /usr/local/sbin/ipaddress

usage() {
  cat <<EOF
Usage: $(basename $0) [interface]

Report the IP 4 address for the default interface (or the one given in the params)
(default interface is computed from the default route)

EOF
}

main() {
  show_usage_and_exit_if_requested $@
  local default=$(default_network_interface)
  local interface=${1:-$default}
  inet_addr_for_interface $interface
}

show_usage_and_exit_if_requested() {
  if <<<"$@" egrep -q '(--help|-h)'; then
    usage
    exit 1
  fi
}

default_network_interface() {
  ip route | awk '/default/ {print $NF}'
}

inet_addr_for_interface() {
  ifconfig $1 | awk -F'[ :]+' '/inet addr:/ {print $4}'
}

main $@