ipcalc 1.0.3 (The man file)

ipcalc is a modern tool to assist in network address calculations for IPv4 and
IPv6. It acts both as a tool to output human readable information about a
network or address, as well as a tool suitable to be used by scripts or other
programs.  It supports printing a summary about the provided network address,
multiple command line options per information to be printed, transparent IPv6
support, and in addition it will use libGeoIP if available to provide
geographic information.

https://gitlab.com/ipcalc/ipcalc