ip-neighbour:tldr:d3415

This command is used to flush (clear) the ARP (Address Resolution Protocol) cache for a specified network interface (${eth0}) using the sudo command to gain root or superuser privileges.

In more detail:

• sudo is a command that allows a user to execute a command with administrative or superuser privileges. It prompts the user to enter their password, and if authenticated, grants them the necessary permissions to execute the subsequent command.
• ip neighbour is a command used to manage and display the neighbor cache, which is responsible for storing the mappings between IP addresses and MAC addresses.
• flush is an argument or option provided to the ip neighbour command.
• dev ${eth0} is another argument to specify the network interface (${eth0} refers to the value or variable representing the network interface name) for which the neighbor cache should be cleared.

Overall, this command allows the user to clear the ARP cache for a particular network interface, which can be helpful in troubleshooting network connectivity issues or updating the MAC address mappings for a specific device.