Miscellaneous Features


Turn the timer setting on, and cmd2 will show the wall time it takes for each command to execute.


Mention quit, and EOF handling built into cmd2.

Shell Command

cmd2 includes a shell command which executes it’s arguments in the operating system shell:

(Cmd) shell ls -al

If you use the default Shortcuts defined in cmd2 you’ll get a ! shortcut for shell, which allows you to type:

(Cmd) !ls -al

Commands At Invocation

You can send commands to your app as you invoke it by including them as extra arguments to the program. cmd2 interprets each argument as a separate command, so you should enclose each command in quotation marks if it is more than a one-word command.

$ python examples/example.py "say hello" "say Gracie" quit


If you wish to disable cmd2’s consumption of command-line arguments, you can do so by setting the allow_cli_args argument of your cmd2.Cmd class instance to False. This would be useful, for example, if you wish to use something like Argparse to parse the overall command line arguments for your application:

from cmd2 import Cmd
class App(Cmd):
    def __init__(self):

Initialization Script

You can execute commands from an initialization script by passing a file path to the startup_script argument to the cmd2.Cmd.__init__() method like so:

class StartupApp(cmd2.Cmd):
    def __init__(self):
        cmd2.Cmd.__init__(self, startup_script='.cmd2rc')

This text file should contain a Command Script. See the AliasStartup example for a demonstration.


Presents numbered options to user, as bash select.

app.select is called from within a method (not by the user directly; it is app.select, not app.do_select).

Cmd.select(opts: Union[str, List[str], List[Tuple[Any, Optional[str]]]], prompt: str = 'Your choice? ') → str

Presents a numbered menu to the user. Modeled after the bash shell’s SELECT. Returns the item chosen.

Argument opts can be:

a single string -> will be split into one-word options
a list of strings -> will be offered as options
a list of tuples -> interpreted as (value, text), so that the return value can differ from the text advertised to the user
def do_eat(self, arg):
    sauce = self.select('sweet salty', 'Sauce? ')
    result = '{food} with {sauce} sauce, yum!'
    result = result.format(food=arg, sauce=sauce)
    self.stdout.write(result + '\n')
(Cmd) eat wheaties
    1. sweet
    2. salty
Sauce? 2
wheaties with salty sauce, yum!

Disabling Commands

cmd2 supports disabling commands during runtime. This is useful if certain commands should only be available when the application is in a specific state. When a command is disabled, it will not show up in the help menu or tab complete. If a user tries to run the command, a command-specific message supplied by the developer will be printed. The following functions support this feature.

Enable an individual command
Enable an entire category of commands
Disable an individual command and set the message that will print when this command is run or help is called on it while disabled
Disable an entire category of commands and set the message that will print when anything in this category is run or help is called on it while disabled

See the definitions of these functions for descriptions of their arguments.

See the do_enable_commands() and do_disable_commands() functions in the HelpCategories example for a demonstration.

Exit code

The self.exit_code attribute of your cmd2 application controls what exit code is returned from cmdloop() when it completes. It is your job to make sure that this exit code gets sent to the shell when your application exits by calling sys.exit(app.cmdloop()).

Default to shell

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

(Cmd) shell which python
(Cmd) !which 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
(Cmd) my dog has fleas
sh: my: not found
*** Unknown syntax: my dog has fleas

Quit on SIGINT

On many shells, SIGINT (most often triggered by the user pressing Ctrl+C) only cancels the current line, not the entire command loop. By default, a cmd2 application will quit on receiving this signal. However, if quit_on_sigint is set to False, then the current line will simply be cancelled.

(Cmd) typing a comma^C


The default SIGINT behavior will only function properly if cmdloop is running in the main thread.