Head and Tail functions

[eried]

How to use head and tail with strings inside a program?

It seems quite inconsistent:

Code:

HOME:
tail("hola"); // return empty matrix
head("hola"); // return the same string

Syntax error if used uppercades (with msgbox)

Code:

CAS:
tail("hola"); // correct
head("hola"); // correct

Weird error if used uppercased (no msgbox) but return:
of(["Error: Bad Argument Value"])

Inside a program it seems to work like as in HOME, with or without CAS. in front