VyOS ver 1.2.7:
vyos@vyos:~$ clear interfaces dummy Possible completions: counters Clear all dummy interfaces counters dummy0 Clear interface information for a given dummy interface
VyOS ver 1.4-rolling-202106131819 & 1.3-beta-202106131928
vyos@R3:~$ clear interfaces dummy Possible completions: counters Clear all dummy interfaces counters
The command should show the available list of dummy interfaces dumN