=========================================
Features requiring only parameter changes
=========================================

Several aspects of a ``cmd2`` application's behavior
can be controlled simply by setting attributes of ``App``.
A parameter can also be changed at runtime by the user *if* 
its name is included in the dictionary ``app.settable``.
(To define your own user-settable parameters, see :ref:`parameters`)

Case-insensitivity
==================

By default, all ``cmd2`` command names are case-insensitive; 
``sing the blues`` and ``SiNg the blues`` are equivalent.  To change this, 
set ``App.case_insensitive`` to False.

Whether or not you set ``case_insensitive``, *please do not* define
command method names with any uppercase letters.  ``cmd2`` will probably
do something evil if you do.
 
Shortcuts
=========

Special-character shortcuts for common commands can make life more convenient for your
users.  Shortcuts are used without a space separating them from their arguments,
like ``!ls``.  By default, the following shortcuts are defined:

  ``?``
    help
    
  ``!`` 
    shell: run as OS-level command
    
  ``@``
    load script file
    
  ``@@``
    load script file; filename is relative to current script location
    
To define more shortcuts, update the dict ``App.shortcuts`` with the
{'shortcut': 'command_name'} (omit ``do_``)::

  class App(Cmd2):
      Cmd2.shortcuts.update({'*': 'sneeze', '~': 'squirm'})

Default to shell
================

Every ``cmd2`` application can execute operating-system
level (shell) commands with ``shell`` or a ``!``
shortcut::

  (Cmd) shell which python
  /usr/bin/python
  (Cmd) !which python
  /usr/bin/python

However, if the parameter ``default_to_shell`` is 
``True``, then *every* command will be attempted on
the operating system.  Only if that attempt fails
(i.e., produces a nonzero return value) will the
application's own ``default`` method be called.

::

  (Cmd) which python
  /usr/bin/python
  (Cmd) my dog has fleas
  sh: my: not found
  *** Unknown syntax: my dog has fleas

Timing
======

Setting ``App.timing`` to ``True`` outputs timing data after
every application command is executed.  |settable|

Echo
====

If ``True``, each command the user issues will be repeated
to the screen before it is executed.  This is particularly
useful when running scripts.

Debug
=====

Setting ``App.debug`` to ``True`` will produce detailed error stacks
whenever the application generates an error.  |settable|

.. |settable| replace:: The user can ``set`` this parameter
                        during application execution.  
                        (See :ref:`parameters`)


Other user-settable parameters
==============================

A list of all user-settable parameters, with brief
comments, is viewable from within a running application
with::

  (Cmd) set --long
  abbrev: True                   # Accept abbreviated commands
  case_insensitive: True         # upper- and lower-case both OK
  colors: True                   # Colorized output (*nix only)
  continuation_prompt: >         # On 2nd+ line of input
  debug: False                   # Show full error stack on error
  default_file_name: command.txt # for ``save``, ``load``, etc.
  echo: False                    # Echo command issued into output
  editor: gedit                  # Program used by ``edit``
  feedback_to_output: False      # include nonessentials in `|`, `>` results
  prompt: (Cmd)                  # 
  quiet: False                   # Don't print nonessential feedback
  timing: False                  # Report execution times