Debug Syntax

To quickly print information about a variable when debugging, it can be printed with a question mark after the dollar sign, e.g. $?myVar. This will print the variable name, type and all in-context values. In HTML mode, styles and colors are applied to distinguish the output and values from one another; for example, empty values have a light-green background. Even more debug information can be printed with two question marks, e.g. $??myVar, such as script and line number, variable scope, and referenced source variable. Both syntaxes are legal only when printing, i.e. not for parameter passing etc. The format and content of the output is intended for short-term debugging, not production scripts, and may change in a future release. These syntaxes were added in version 6. See also <varinfo dump>, here.