Tcm.exe is an application that can be used to creates test cases from test methods, we can also run test cases with associated automation test instead of using the user interface so it can be run with the nightly build batch
When you start the run from the command line, use tcm.exe. You must specify both the test settings that contain the set of roles that you require to run your tests, and an environment that contains this set of roles.
Tcm.exe is a command-line utility that lets you perform the following tasks:
- Import automated tests into a test plan
- Run tests that are part of a test plan from the command line
- View a list of test items and their corresponding IDs to use when you import tests or run tests
for more information see the following link