What is the command to list the available avdnames

Using sdk/tools/emulator

This will list all available avds

emulator -list-avds

android shell configuration adb avd

AFAIK avdmanager list avd is what you need.

android shell configuration adb avd

get into Android/sdk/tools and run following command

./emulator -list-avds

which will return something like

Nexus_5X_API_PNexus_6_API_25

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