The Ansible command module is the default module that ansible. It is used to execute Binary Commands.
The command module will execute if we do not specific module name in Ansible Ad-Hoc commands.
ansible localhost -m command -a "uptime"
In the above example, we are passing the module as a command, if we skip the module name, ansible will still execute the command and will pick the command as the default module, the output will be the same for both ad-hoc commands.
ansible localhost -a "uptime"