Get current IP address

$ hostname -I

ip command

Linux only, not macOS.

From tutorial. That explains what the output means.

Use one of these equivalent commands.

$ ip address show
$ ip addr show
$ ip addr
$ ip a

To look-up for specific network:

$ ip addr show dev lo
$ ip addr show dev enp0s3

ifconfig

On Linux and macOS.

$ ifconfig en0

en0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
	options=400<CHANNEL_IO>
	ether 88:e9:fe:57:a8:6b
	inet6 fe80::1c4a:70f:5ec6:fb68%en0 prefixlen 64 secured scopeid 0x5
	inet 192.168.0.161 netmask 0xffffff00 broadcast 192.168.0.255
	nd6 options=201<PERFORMNUD,DAD>
	media: autoselect
	status: active

Routes

See IP routes on your machine.

$ ip route

Check connection

Request an address every second.

This is useful to check an IP on your network.

$ ping 192.168.4.44

Or that a site is reachable.

$ ping https://google.com

Understanding IP address ranges

Any machine can connect to the host.

0.0.0.0

Maximum values.

255.255.255.255

Address of your machine.

127.0.0.1
localhost
[::]

Typical address of your router.

192.168.0.1
192.168.8.1

When configuring, you’ll see slash notation at the end of an IP range.

It is the number of bits allowed that are fixed - 24, 8 or 16.

The /24 here indicates that the first 24 bits are part of the network address (192.168.10) leaving only the remaining 8 bits able to be changed for specific host addresses (0-254).

IP Range Description
10.0.0.0/24 10.0.0.1 – 10.0.0.254 Can assign the last number
10.0.0.0/16 10.0.0.1 – 10.0.255.254 Can assign the last two numbers
10.0.0.0/8 10.0.0.1 – 10.255.255.254 Can assign the last three numbers

The limits are short for octet masks which are applied. Note a mask is inverted so 255 becomes 0 and means the octet can only be 0 and if the mask is 0 then it means the max is 255 so you have 0-255.

Short Subnet mask Total IP addresses
/32 255.255.255.255 1
/24 255.255.255.0 256
/16 255.255.0.0 65,536
/8 255.0.0.0 16,777,216

See this table of subnet masks.