`mesheryctl adapter validate` "Error: required flag(s) "spec" not set"

I tried mesheryctl adapter validate -a --spec and mesheryctl adapter validate -a -s but I still got this Error: required flag(s) "spec" not set Any help? thanks!

Adapter for required mesh not found Adapter for required mesh not found Verifying prerequisites... 
Unable to sync with available adapters. : 
Adapter for required mesh not found 
verified prerequisites 
Error: required flag(s) "spec" not set

It’s time to deprecate and remove the “validate” command.