-``-D`` or ``--details`` reports the path name where the specified function is defined or could be autoloaded, ``stdin`` if the function was defined interactively or on the command line or by reading stdin, ``-`` if the function was created via :ref:`source <cmd-source>`, and ``n/a`` if the function isn't available. (Functions created via :ref:`alias <cmd-alias>` will return ``-``, because ``alias`` uses ``source`` internally.) If the ``--verbose`` option is also specified then five lines are written:
- the line number within the file or zero if not applicable,
-``scope-shadowing`` if the function shadows the vars in the calling function (the normal case if it wasn't defined with ``--no-scope-shadowing``), else ``no-scope-shadowing``, or ``n/a`` if the function isn't defined,
- the function description minimally escaped so it is a single line or ``n/a`` if the function isn't defined.
The default behavior of ``functions``, when called with no arguments, is to print the names of all defined functions. Unless the ``-a`` option is given, no functions starting with underscores are included in the output.
The exit status of ``functions`` is the number of functions specified in the argument list that do not exist, which can be used in concert with the ``-q`` option.