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One Day One Command
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ipcalc — Simple IP address manipulation tool.

Summary:

ipcalc provides a simple way to calculate IP information for a host.
The various options specify what information ipcalc should display on
standard out.

Examples:

$ ipcalc -b 192.168.13.175/24 — Display the broadcast address.

$ ipcalc -h 192.168.13.1 — Display the Host name of the IP.

$ ipcalc -m 192.168.13.1/25 — Calculate and Show the netmask.

$ ipcalc -p 192.168.13.1 255.255.200.0 — Display the prefix count.

$ ipcalc -n 192.168.13.1/21 — Show the Network address.

Read: man ipcalc