yes potatoes >>potatoes

Yes is also very fast if you want a text file to fill the disk. But don’t run it XD

This might go beyond what you were asking for, but I’m always more comfortable handling file paths, deletions and errors in Python.

#!/usr/bin/env python3

import shutil
from pathlib import Path
from tempfile import TemporaryDirectory

# Refuse to run without Python's symlink-resistant cleanup.
if not getattr(shutil.rmtree, "avoids_symlink_attacks", False):
    raise RuntimeError("Symlink-resistant cleanup is unavailable")

with TemporaryDirectory(prefix="test-run-", dir="/tmp") as name:
    tests = Path(name) / "tests"
    tests.mkdir(mode=0o700)
    print(f"Created {str(tests)!r}", flush=True)

    try:
        # Put your test code here.
        (tests / "example.txt").write_text(
            "temporary data\n", encoding="utf-8"
        )
    finally:
        print(f"Cleaning {name!r}", flush=True)

# The entire temporary directory has now been removed.