myip

#!/bin/sh
#
# @author JC <https://github.com/joncutrer>
# @version 0.1.1
# @license MIT

VERSION="0.1.1"
USAGE=$(cat <<-EOF
Get the default IP address of the machine.
The one you are always after when you type ifconfig
The IP assigned to the interface that the default route belongs to

Syntax & Example Usage

  myip            Print the primary IP Address
  myip ip         Verbose, same as above cmd
  myip if         Print only the default interface name
  myip sm         Print only the subnet mask
  myip gw         Print only the default gateway IP
  myip all        Print all; ifname ipaddr mask gw
  myip help       Print this information

Command Line Options
  -v,--version:  Print Version Number
  -h,--help:     Alias for help
  -a,--all:      TODO: Print all configured IP addresses
  -l,--list:     TODO: Print all Interface Name and IPs, one per line 
  --cidr:        TODO: Show IP with CIDR subnet mask i.e. /24
  --csv:         TODO: Output in CSV format

EOF
)

def_if=`ip route list | grep -e "^default" | awk '{print $5}'`
def_gw=`ip route list | grep -e "^default" | awk '{print $3}'`
def_ip=`ifconfig $def_if | grep "inet addr" | cut -d ':' -f 2 | cut -d ' ' -f 1`
def_sm=`ifconfig $def_if | grep "inet addr" | cut -d ':' -f 4 | cut -d ' ' -f 1`


if [ -z "$1" ] || [ "$1" == "ip" ]; then 
        echo "$def_ip"
        exit
fi

if [ "$1" == "if" ]; then
        echo $def_if
        exit
fi

if [ "$1" == "sm" ]; then
        echo $def_sm                    
        exit
fi

if [ "$1" == "gw" ]; then
        echo $def_gw     
        exit
fi 

if [ "$1" == "all" ]; then
        echo "$def_if $def_ip $def_sm $def_gw"
        exit
fi

if [ "$1" == "help" ]  || [ "$1" == "-h" ]  || [ "$1" == "--help" ]; then
        echo "$USAGE"
        exit
fi

if [ "$1" == "-v" ] || [ "$1" == "--version" ]; then                   
        echo "$VERSION"                         
        exit
fi