remove regex matched text in texts of a dir

main.rs

//! need regex = "1.5"
use regex::Regex;
use std::env;
use std::fs;
use std::path::PathBuf;
fn main() {
    // default is to remove header(better reading for some htmls exported by singleFile, like oreilly, etc)
    let mut reg_str= r"<header.*>(.|\n)*?</header>";
    let args :Vec<String> = env::args().collect();
    let dir;
    if args.len() <= 1 {
        // default dir is current dir
        dir = ".".to_owned();
    } else if args.len() <= 2 {
        dir = args[1].clone();
    } else {
        dir = args[1].clone();
        reg_str = &args[2];
    }
    let regex = Regex::new(reg_str).unwrap();
    for entry in fs::read_dir(&dir).unwrap() {
        let e = entry.unwrap();
        if !e.file_type().unwrap().is_file() {
            continue;
        }
        let path = e.path();
        let content = fs::read_to_string(&path).unwrap();
        let replaced = regex.replace(&content, "").to_string();
        let mut new_path = PathBuf::from(&dir);
        new_path.push("replaced");
        // ignore
        let _ = fs::create_dir(new_path.to_str().unwrap());
        new_path.push(e.file_name());
        println!("{path:?} ---> {new_path:?}");
        fs::write(new_path, replaced).unwrap();
    }
}