add description for sweep to Readme

README.md

@@ -32,6 +32,12 @@ The following command will evaluate the probe from the run naughty-northcutt on
 elk eval naughty-northcutt microsoft/deberta-v2-xxlarge-mnli imdb
 ```
 
+The following runs `elicit` on the Cartesian product of the listed models (gpt2 gpt2-medium gpt2-large gpt2-xl) and datasets (imdb amazon_polarity), storing it in a special folder ELK_DIR/sweeps/<memorable_name>:
+
+```bash
+elk sweep --models gpt2 gpt2-medium gpt2-large gpt2-xl --datasets imdb amazon_polarity
+```
+
 ## Caching
 
 The hidden states resulting from `elk elicit` are cached as a HuggingFace dataset to avoid having to recompute them every time we want to train a probe. The cache is stored in the same place as all other HuggingFace datasets, which is usually `~/.cache/huggingface/datasets`.