If you would like to list all AWS Lambda Function Names in your CLI using the AWS CLI, then you can do this:
Get a List of all Lambda Functions
aws lambda list-functions
However, note that this will return a potentially large JSON payload back to your CLI. So what if you only want a list of the function names themselves?
You can couple the AWS command above, with the jq command as follows:
Get a List of all Lambda Function Names
aws lambda list-functions | jq '.Functions[].FunctionName'