#### 10.2.8 real-thing

The various implementations of SCCS vary in several different ways, but the CSSC test suite tries very hard to pass when run against any genuine implementation of SCCS unless it has a definite bug. This means for example that although the CSSC version of `admin -i` will support automatic switch-over to binary mode for a file provided via stdin, and the test suite tests this, the same property is not required of SCCS itself.

The `real-thing` script checks if we are actually tesing a real implementation of SCCS. It sets the environment variable `TESTING_CSSC` to ‘`true`’ or ‘`false`’, depending on whether we are testing CSSC or not.

If you are really interested in whether the implementation being tested supports binary files or not, you should be using the `config-data` script instead.