Networking – Ubuntu 18 Command to Enable and Disable a USB Ethernet Card

I have a USB Ethernet card that works well with Ubuntu 18.04. Now I have to find a way to turn it on and off with command.

I have tried the command sudo ip l s dev enx00249b450d4d down (enx00249b450d4d is the name of the interface), but nothing changes.

I've also installed net-tools and tried the command sudo ifconfig enx00249b450d4d downbut was not lucky either.

I've searched the internet, but the information on Ubuntu 18 is still rare. An idea?