File Read

Read files with std::fs.

Difficulty

Intermediate

Code

use std::fs;

fn main() -> Result<(), Box<dyn std::error::Error>> {
    // read entire file
    let content = fs::read_to_string("Cargo.toml")?;
    println!("first line: {}", content.lines().next().unwrap_or(""));

    // read bytes
    let bytes = fs::read("Cargo.toml")?;
    println!("file size: {} bytes", bytes.len());

    Ok(())
}

Explanation

This example demonstrates how to use file read in Rust. Read the code carefully to understand the flow. Pay attention to where values are created, borrowed, moved, or consumed.

Key Concepts

• Rust's strong type system catches errors at compile time
• Ownership and borrowing rules ensure memory safety
• Pattern matching makes code expressive and exhaustive

Related Topics

Browse more examples in the file-io category to build a complete understanding of this topic.