    The user file-creation mask is set to MODE.  If MODE is omitted, or if
    `-S' is supplied, the current value of the mask is printed.  The `-S'
    option makes the output symbolic; otherwise an octal number is output.
    If `-p' is supplied, and MODE is omitted, the output is in a form
    that may be used as input.  If MODE begins with a digit, it is
    interpreted as an octal number, otherwise it is a symbolic mode string
    like that accepted by chmod(1).
