Write a string to a file

The fs.write function is used to write a string to a file. The first argument is a string of the file path, and the second argument is a string or std.io.Bytes of the content.

If the file does not exist, it will create a new file. If the file exists, it will overwrite the file content.

use std.fs;

fn main() throws {
    try fs.write("output.txt", "Hello, world!\n");
}

Then the output.txt file will contain the following content:

Hello, world!

Alternative

You can use fs.open or File.open method to open a file in write mode and get a std.fs.File instance, and use the write method to write a bytes to the file, use write_string method to write a string to the file.

In this case, you must special the flag argument to open the file in write mode (the default flag is fs.READ, that means read-only mode). So you must use fs.WRITE flag to open the file in write mode. And with fs.CREATE flag, it will create a new file if the file does not exist.

use std.fs;

fn main() throws {
    let f = try fs.open("output.txt", flag: fs.WRITE | fs.CREATE);
    defer {
        try! f.close();
    }
    try f.write_string("Hello, world!\n");
}