How to modify/update or remove/delete credentials with the command line utility tw_vault_control?

Before going further, please note that the preferred method to modify/delete credentials is to use the rest apis. 

1- UPDATE:
Example modification of an 'AWS' credential:

1) Find the id of the relevant credential to delete using the following command line:

tw_vault_control --show --type=aws
82c47635cd5395765f160a65003d393a
        [...]
        label = "this is the label of the credential that the user wants to update"

2) Create a JSON file for a specific credential ID:

tw_vault_control --show --id=82c47635cd5395765f160a65003d393a --json >> aws.json

or, just dump all of the AWS credentials to the json file, like this:

tw_vault_control --show --type=aws --json >> aws.json

3) Edit the JSON file with new info, and remove all occurrences of "*MASKED*"
4) Push the changes to the credentials:

tw_vault_control --update aws.json

This step could be automated with a custom script (not provided in this article).