Download / Installation

# wget https://raw.githubusercontent.com/YoungjuWang/scanip/master/scanip/scanip
# chmod +x scanip; mv scanip /usr/local/bin/

Help

# scanip --help
Using ICMP. Check used/unused ip addresses. If your system block ICMP packet, "scanip" cannot work well

Usage:
  scanip [flags]

Examples:
scanip -c 192.168.0.0/24

Flags:
  -a, --all           Print all addresses (default true)
  -c, --cidr string   Network CIDR (required)
  -h, --help          help for scanip
  -x, --unused        Print unused addresses
  -o, --used          Print used addresses

All list of Address usgae state

$ sudo scanip -c 172.16.20.0/24

IP_Address              Used
=================================
172.16.20.0     Network Address
172.16.20.1             O
172.16.20.2             O
172.16.20.3             X
172.16.20.4             O
172.16.20.5             X
172.16.20.6             X
172.16.20.7             X
172.16.20.8             X
172.16.20.9             X
172.16.20.10            O
172.16.20.11            X
(...)

Get only used/unused addresses

used

sudo scanip -c 172.16.20.0/24 -o
IP_Address              Used
=================================
172.16.20.0     Network Address
172.16.20.1             O
172.16.20.2             O
172.16.20.4             O
172.16.20.10            O
172.16.20.15            O
172.16.20.16            O
(...)
172.16.20.255       Broadcast Address

unused

sudo scanip -c 172.16.20.0/24 -x
IP_Address              Used
=================================
172.16.20.3             X
172.16.20.5             X
(...)