# Python in batch jobs

By default, `print` in Python is buffered. When running Python in a batch job in SLURM you may see output less often than you would when running interactively. This is because the output is being buffered - the print statements are collected until there is a large amount to print, then the messages are all printed at once. For debugging or checking that a Python script is producing the correct output, you may want to switch off buffering.

## Switch off buffering

For a single python script you can use the `-u` option, e.g.

```bash
python -u my_script.py
```

The `-u` stands for "unbuffered". You can use the environment variable `PYTHONUNBUFFERED` to set unbuffered I/O for your whole batch script.

```bash
#!/bin/bash
#SBATCH -n 1

export PYTHONUNBUFFERED=TRUE
python my_script.py
```

There is some performance penalty for having unbuffered print statements, so you may want to reduce the number of print statements, or run buffered for production runs.


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.ccv.brown.edu/oscar/software/python-in-batch-jobs.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.