ipaddr is a command-line tool for manipulating and querying IP addresses and networks. It provides functionality similar to Python's ipaddress module but as a standalone CLI utility. Features include: - IPv4 and IPv6 address normalization - CIDR and netmask prefix notation support - Network calculations (network, broadcast, host addressing) - Address classification (private, loopback, multicast, etc.) - Subnet and supernet operations - Command chaining for complex operations - IPv6-specific features (6to4, Teredo, zone-id)