ifconfig - linux

ifconfig (short for interface configuration) is a system administration utility in Unix-like operating systems to configure, control, and query TCP/IP network interface parameters from a command line interface (CLI) or in system configuration scripts. Ifconfig originally appeared in 4.2BSD as part of the BSD TCP/IP suite.

Ifconfig is used to configure the kernel-resident network interfaces. It is used at boot time to set up interfaces as necessary.
After that, it is usually only needed when debugging or when system tuning is needed.

If no arguments are given, ifconfig displays the status of the currently active interfaces. If a single interface argument is given,
it displays the status of the given interface only; if a single -a argument is given, it displays the status of all interfaces, even
those that are down. Otherwise, it configures an interface.