cmd is the Python Standard Library's module for creating simple interactive command-line applications. cmd is an extremely bare-bones framework which leaves a lot to be desired. It doesn't even include a built-in way to exit from an application!
Since the API provided by cmd provides the foundation on which cmd2
is
based, understanding the use of cmd is the first step in learning the use of
cmd2
. Once you have read the cmd docs, return here to learn the ways that
cmd2
differs from cmd.
cmd2
is a batteries-included extension of cmd, which provides a wealth of
functionality to make it quicker and easier for developers to create
feature-rich interactive command-line applications which delight customers.
cmd2
can be used as a drop-in replacement for cmd with a few minor
discrepancies as discussed in the
:ref:`migrating/incompatibilities:Incompatibilities` section. Simply importing
cmd2
in place of cmd will add many features to an application without any
further modifications. Migrating to cmd2
will also open many additional
doors for making it possible for developers to provide a top-notch interactive
command-line experience for their users.
After switching from cmd to cmd2
, your application will have the following
new features and capabilities, without you having to do anything:
- More robust :ref:`features/history:History`. Both cmd and
cmd2
have readline history, butcmd2
also has a robusthistory
command which allows you to edit prior commands in a text editor of your choosing, re-run multiple commands at a time, and save prior commands as a script to be executed later. - Users can redirect output to a file or pipe it to some other operating system
command. You did remember to use
self.stdout
instead ofsys.stdout
in all of your print functions, right? If you did, then this will work out of the box. If you didn't, you'll have to go back and fix them. Before you do, you might consider the various wayscmd2
has of :ref:`features/generating_output:Generating Output`. - Users can load script files, which contain a series of commands to be executed.
- Users can create :ref:`features/shortcuts_aliases_macros:Shortcuts, Aliases, and Macros` to reduce the typing required for repetitive commands.
- Embedded python shell allows a user to execute python code from within your
cmd2
app. How meta. - :ref:`features/clipboard:Clipboard Integration` allows you to save command output to the operating system clipboard.
- A built-in :ref:`features/misc:Timer` can show how long it takes a command to execute
- A :ref:`Transcript <features/transcripts:Transcripts>` is a file which
contains both the input and output of a successful session of a
cmd2
-based app. The transcript can be played back into the app as a unit test.
In addition to the features you get with no additional work, cmd2
offers a
broad range of additional capabilties which can be easily added to your
application. :ref:`migrating/next_steps:Next Steps` has some ideas of where
you can start, or you can dig in to all the :ref:`features/index:Features`.