Operating system shells have long had the ability to execute a sequence of commands saved in a text file. These script files make long sequences of commands easier to repeatedly execute. cmd2 supports two similar mechanisms: command scripts and python scripts.

Command Scripts

A command script contains a sequence of commands typed at the the prompt of a cmd2 based application. Unlike operating system shell scripts, command scripts can’t contain logic or loops.

Creating Command Scripts

Command scripts can be created in several ways:

  • creating a text file using any method of your choice
  • using the built-in edit command to create or edit an existing text file
  • saving previously entered commands to a script file using history -s

If you create create a text file from scratch, just include one command per line, exactly as you would type it inside a cmd2 application.

Running Command Scripts

Command script files can be executed using the built-in run_script command or the @ shortcut (if your application is using the default shortcuts). Both ASCII and UTF-8 encoded unicode text files are supported. The run_script command supports tab completion of file system paths. There is a variant _relative_run_script command or @@ shortcut (if using the default shortcuts) for use within a script which uses paths relative to the first script.


Any command line input where the first non-whitespace character is a # will be treated as a comment. This means any # character appearing later in the command will be treated as a literal. The same applies to a # in the middle of a multiline command, even if it is the first character on a line.

Comments are useful in scripts, but would be pointless within an interactive session.

(Cmd) # this is a comment
(Cmd) command # this is not a comment

Python Scripts

If you require logic flow, loops, branching, or other advanced features, you can write a python script which executes in the context of your cmd2 app. This script is run using the run_pyscript command. Here’s a simple example that uses the arg_printer script:

(Cmd) run_pyscript examples/scripts/ foo bar 'baz 23'
Running Python script '' which was called with 3 arguments
arg 1: 'foo'
arg 2: 'bar'
arg 3: 'baz 23'

run_pyscript supports tab completion of file system paths, and as shown above it has the ability to pass command-line arguments to the scripts invoked.

Python scripts executed with run_pyscript can run cmd2 application commands by using the syntax:

app(‘command args’)


  • app is a configurable name which can be changed by setting the cmd2.Cmd.py_bridge_name attribute
  • command and args are entered exactly like they would be entered by a user of your application.

See python_scripting example and associated conditional script for more information.

Advanced Support

When implementing a command, setting self.last_result allows for application-specific data to be returned to a python script from the command. This can allow python scripts to make decisions based on the result of previous application commands.

The application command (default: app) returns a cmd2.CommandResult for each command. The cmd2.CommandResult object provides the captured output to stdout and stderr while a command is executing. Additionally, it provides the value that command stored in self.last_result.

Additionally, an external test Mixin plugin has been provided to allow for python based external testing of the application. For example, for system integration tests scenarios where the python application is a component of a larger suite of tools and components. This interface allows python based tests to call commands and validate results as part of a larger test suite. See External Test Plugin