The dollar sign, $, has a special meaning in the Pine resource
    file: it means that the word following it is an "environment
    variable", i.e., a DCL symbol or logical name, the value of which
    is then substituted at that point in the file. To specify $ in a
    value, you need to prefix it with a backslash; e.g.,

    SYS\$LOGIN:SIGNATURE.TXT