The system includes a set of special commands called dot commands. The system intercepts commands that are preceded by a period and uses them to perform special functions in the system.
Most dot commands must be used in the command field of a step, but a few, the environment dot commands, can be used in environment variables. See Environment Dot Commands for instructions.
You can mix dot commands with ordinary commands in a step and you can have multiple dot commands in a single step. Do not use more than one .scan command in a single step, however, as the system cannot accurately report the command's results if you do.