To ping a specific gateway interface or source IP address from the Linux or Unix command line, you can use the ping utility with the -I option.
Here is an example of how to use the ping utility to ping a specific gateway interface:
ping -I interface destination
This will send a ping request to the specified destination using the specified interface. The interface can be the name of a network interface, such as eth0 or wlan0, or the IP address of a gateway.
Here is an example of how to use the ping utility to ping a specific source IP address:
ping -I source destination
This will send a ping request to the specified destination using the specified source IP address as the source of the ping request.
It's important to note that the -I option may not be available on all versions of the ping utility. Consult the ping documentation and online resources for more information on how to use this option.
You can also use other tools and utilities, such as nc (netcat) or traceroute, to ping specific gateway interfaces or source IP addresses. Consult the documentation and online resources for more information.