Scripting

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. See History for more details.

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 @ shortcut. 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 for use within a script which uses paths relative to the first script.

Comments

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. See Embedded Python Shells.