Using the command "list" and "clear" and "add" and "add" with valid addressbook input has unexpected behaviour

[nus-se-bot]

Describe the bug
"list" and "clear" and "add" and "add" with valid addressbook input commands results in "Listed all persons" and "Addressbook has been cleared" and "Invalid command format!
add: Adds a person to the address book. Parameters: n/NAME p/PHONE e/EMAIL a/ADDRESS [t/TAG]...
Example: add n/John Doe p/98765432 e/johnd@example.com a/311, Clementi Ave 2, #2-25 t/friends t/owesMoney" and "New person added: chicken Phone: 123412 Email: and@gmail.com Address: 1jasbdabs Tags:" respectively

To Reproduce
Steps to reproduce the behavior:

1. run command "list"

To Reproduce
Steps to reproduce the behavior:

1. run command "clear"

To Reproduce
Steps to reproduce the behavior:

1. run command "add"

To Reproduce
Steps to reproduce the behavior:

1. run command "add n/chicken p/123412 e/and@gmail.com a/1jasbdabs"

To Reproduce
Steps to reproduce the behavior:

1. run command "delete"

Expected behavior
"list" an error message should have been displayed or if its an alias for "listfiles" should list all files
"clear" an error message or something related to FomoFoto
same for "add" and "add" with valid addressbook input and "delete"

Screenshots

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Reported by: @Qing-Yuan
Severity: Low

_{[original: nus-cs2103-AY1819S2/pe-dry-run#501]}

[ghost]

Fixed with #195. All aformentioned commands have been removed.