Variables hold simple strings. They are global and come in two types: temporary and permanent. Permanent variables persist over multiple invocations of the chat script, while temporary variables are forgotten each time the script completes.
Variables are specified with a dollar sign, then a letter, followed by letters, digits, and underscores. If the first letter is upper case the variable is permanent; otherwise it is temporary. The variable name may be optionally enclosed in curly braces.
Examples:
$initString
$My_variable_234
${i_am_safely_followed_by_a_letter}