Update All Files Recursively In A Directory With A Give Extension With Rust

July 2023

This is a very simple process that recursively loops over a directory and updates any files with a given extension:

use std::fs;
use std::path::PathBuf;
use walkdir::WalkDir;

fn main() {
    update_files("some/path");
}

fn update_file(file_path: PathBuf) {
    let contents = fs::read_to_string(&file_path).unwrap();
    if !contents.contains("-- site:") {
        let mut new_contents = contents.trim_end().to_string();
        new_contents.push_str("\n-- site: aws\n");
        let _ = fs::write(file_path, new_contents);
    }
}

fn update_files(dir: &str) {
    for entry in WalkDir::new(dir) {
        let pb = entry.unwrap().into_path();
        if match pb.extension() {
            Some(extwrap) => match extwrap.to_str() {
                Some(ext) => match ext {
                    "org" => true,
                    _ => false,
                },
                None => false,
            },
            None => false,
        } {
            update_file(pb);
        }
    }
}

Notes

The update_files function is responsibe for finding the filew with the extension. It passes them to update_file
The update_file function does the work. In this example I'm looking for the string -- site: in the file. I add it to the end of the file (after truncating it) if it's not already there
This code uses the walkdir create that can be installed with cargo add walkdir
One imporvement would be to move the file extension into an argument that's passed to the function
Adding more error handling is also possible, but I'm fine with this panicing if something goes wrong. It's effectively a one-off script.

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References

walkdir