This is my first hands-on experience with Rust. The program actually works and I really like how it functions. I'm just very interested in what code improvements I could do.

I wrote an application in Rust to help me manage my php environments. The binary can be run like:

timpack-cli composer install # run composer install
timpack-cli php72 composer install # run composer install with 'php72'

In the future I want to add in detetection to check what php version should be used.

use std::collections::HashMap;
use std::env;
use std::process::{exit, Command, Output, Stdio};
use std::str;

fn main() {
    let input_arguments: Vec<String> = env::args().collect();

    let interpreters = ["php", "php70", "php71", "php72"];
    let mut interpreter = String::new();
    let mut binary = String::new();

    // Create a hashmap for the command aliases.
    let mut aliases = HashMap::new();
    aliases.insert(string("m1"), string("n98-magerun"));
    aliases.insert(string("m2"), string("n98-magerun2"));
    aliases.insert(string("cc"), string("composer"));

    // Start from index one, since first element is the executed binary, which we don't need right now.
    for i in 1..input_arguments.len() {
        let arg: &str = &input_arguments[i];

        if i == 1 {
            if interpreters.contains(&arg) {
                interpreter = arg.to_string();
            } else  {
                binary = arg.to_string();

        if i == 2 && !interpreter.is_empty() {
            binary = arg.to_string();

    // Fail fast, no binary to run.
    if binary.is_empty() {
        println!("No binary given.");

    // Resolve alias usage if necessary.
    if aliases.contains_key(&binary) {
        binary = aliases.get(&binary).unwrap().to_string();

    let mut executable = binary;
    let mut command_arguments_index = 2;
    let mut command_arguments = Vec::new();

    // Prepare command execution if binary needs to be run with interpreter.
    if !interpreter.is_empty() {
        let output = Command::new("which")
                .expect("Execution of 'which' failed.");


        executable = interpreter;
        command_arguments_index += 1;

    // Push all remaining stdin args to the new command arguments
    for i in command_arguments_index..input_arguments.len() {

    // Run command and wait for status.
    let status = Command::new(executable)
              .expect("Failed to execute command");

    // Exit program with status code of command execution.

 * Create String from str.
fn string(value: &str) -> String {
    return value.to_owned();

 * Get string from Output type.
 * @TODO: What about stderr?
fn output_to_string(output: Output) -> String {
    return String::from_utf8(output.stdout).unwrap().trim().to_string();

Also, it's available on Github, if that's easier.


A couple of things pop out at me.

  1. Prefer `Iterators‘ over “raw” indexing for loops.

    Instead of this

    for i in 1..input_arguments.len()

    You can just loop over the arguments.

    for argument in input_arguments
  2. There’s already a to_string() method on &str. No need to define it yourself.


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