# big-file-gen

Small Python CLI tools for creating and reading large files.
Useful for storage testing, transfer checks, and dumb-fun disk abuse.

## What it does

- create large binary files filled with zeros
- optionally create sparse files instead
- read files back and measure throughput
- optionally compute SHA256 while reading
- no third-party dependencies

## Usage

### Create a file

```bash
python make_big_file.py <output> <size> [--chunk-size SIZE] [--sparse] [--force] [--quiet]
```

Examples:

```bash
python make_big_file.py test.bin 15GB
python make_big_file.py dump.dat 1.5TiB --chunk-size 128MB
python make_big_file.py tiny.bin 500MB --quiet
python make_big_file.py sparse.img 20GB --sparse
python make_big_file.py test.bin 15GB --force
```

### Read a file

```bash
python read_big_file.py <input> [--chunk-size SIZE] [--hash] [--quiet]
```

Examples:

```bash
python read_big_file.py test.bin
python read_big_file.py dump.dat --chunk-size 128MB --hash
python read_big_file.py tiny.bin --quiet
```

## Size formats

Binary units are supported:

- `B`
- `KB`, `MB`, `GB`, `TB`, `PB`
- `KiB`, `MiB`, `GiB`, `TiB`, `PiB`

Plain numbers are treated as bytes.

## Exit codes

- `0` success
- `1` failure
- `130` interrupted

## Requirements

- Python 3.8+
- enough disk space for real writes

## Notes

- `--sparse` is handy when you want a huge file without actually burning the disk.
- `--force` overwrites an existing output file (without it, existing files are protected).
- `--hash` is SHA256, because anything weaker would be cosplay.