How to Read and Write Binary Files in Rust

Use std::fs::File with std::io::Read to read binary data and std::io::Write to write it, handling errors with ? or unwrap().

use std::fs::File;
use std::io::{Read, Write};

fn main() -> std::io::Result<()> {
    let mut file = File::open("data.bin")?;
    let mut buffer = Vec::new();
    file.read_to_end(&mut buffer)?;

    let mut out = File::create("copy.bin")?;
    out.write_all(&buffer)?;
    Ok(())
}

Reading and writing binary files in Rust lets you save and load raw data without converting it to text. You open a file, copy its raw bytes into a list, and then save that list to a new file. Think of it like photocopying a document exactly as it is, without reading or changing the words.