Minimum Required Changes

cmd2.Cmd provides all of the same public methods and fields of cmd.Cmd from the standard library other than Cmd.emptyline (cmd2 never calls this method). Most apps based on the standard library can be migrated to cmd2 in just a couple of minutes.

Import and Inheritance

You need to change your import from this:

import cmd

to this:

import cmd2

Then you need to change your class definition from:

class CmdLineApp(cmd.Cmd):

to:

class CmdLineApp(cmd2.Cmd):

Exiting

Have a look at the commands you created to exit your application. You probably have one called exit and maybe a similar one called quit. You also might have implemented a do_EOF() method so your program exits like many operating system shells. If all these commands do is quit the application, you may be able to remove them. See Exiting.

Distribution

If you are distributing your application, you'll also need to ensure that cmd2 is properly installed. You will need to add the following dependency to your pyproject.toml or setup.py:

'cmd2>=3,<4'

See Integrate cmd2 Into Your Project for more details.