Describe interactive use

README.md

@@ -178,6 +178,27 @@ pass your desired arguments to the Python script to `sbatch`, like so:
 sbatch run.sbatch --train-num-workers=8 --valid-num-workers=3
 ```
 
+### Interactive use
+
+After the environment has been created by executing `bash set_up.sh`
+once on a login node, it can also be used interactively by activating
+it. This activation has to be done in each new terminal session; it
+does not persist between login sessions:
+
+```shell
+source activate.sh
+# Now do whatever you want, for example use `python` interactively.
+```
+
+Keep in mind that you should not be doing heavy work on login nodes.
+Additionally, some libraries that require certain hardware such as
+GPUs may not work on a login node. However, you can also create an
+interactive session on a compute node using `srun --pty`
+
+You can deactivate the Python environment using `deactivate`, however,
+the previous module environment from the module system will not be
+restored.
+
 ### Warnings upon PyTorch Distributed initialization
 
 You can safely ignore warnings like the following: