From a45ac89ef5d2200768477b8d5f5f6da6911ac0a6 Mon Sep 17 00:00:00 2001
From: axtloss <3alouchi2006@gmail.com>
Date: Tue, 5 Oct 2021 17:42:23 +0200
Subject: forgot to save the Readme before pushing

---
 README.md | 64 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 63 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index c846b28..2a6c3e4 100644
--- a/README.md
+++ b/README.md
@@ -1,2 +1,64 @@
 # nix-tool
-Add packages to your configuration.nix only issue: the code is so "optimized" its barely even readable anymore
+Add packages to your configuration.nix </br>
+Except there are two issues:
+- The code is so "optimized" its barely even readble anymore
+- The packages are only accepted via stdin
+
+## Installation
+```sh
+git clone https://github.com/axtloss/nix-tool.git
+cd nix-tool
+rustc -C debuginfo=0 -C embed-bitcode=no -C force-frame-pointers=y -C opt-level=z -C target-cpu=native main.rs -o nix-tool
+# or
+rustc main.rs -o nix-tool
+```
+
+### Usage
+```sh
+echo "<pkgs>" | nix-tool path/to/configuration.nix
+```
+The modified configuration will be saved as `newConfiguration.nix` in the directory where you ran the tool
+
+## How it works
+The code is so small i can dissect it line-by-line and explain it here:
+```rust
+use std::io::{Read, Write};
+```
+This Part just imports `std::io::Read` and `std::io::Write` <br>
+Those were actually the only libraries I couldnt figure out how to use without importing them!<br>
+<br>
+```rust
+fn main() -> Result<(), Box<(dyn std::error::Error + 'static)>> {
+```
+this just is the header of `main` which return some Results of commands<br>
+<br>
+```rust
+let args: std::vec::Vec<String> = std::env::args().collect();
+```
+Here we just read the args the user passed, only the first one is needed but I couldnt figure out how to only import the first arg <br>
+<br>
+```rust
+let mut buffer = String::new();
+```
+We create a new String in which the stdin input will be saved <br>
+<br>
+```rust
+std::io::stdin().read_to_string(&mut buffer)?;
+```
+The stdin input gets read into `buffer` which is also just used once, but I cant figure out how to use it without creating a variable<br>
+<br>
+```rust
+write!(std::fs::File::create("newConfiguration.nix")?, "{}", format!("{}environment.systemPackages = with pkgs;\n  [\n{}\n{}",std::fs::read_to_string(&args[1]).expect("cant open new configuration").split("environment.systemPackages = with pkgs;\n  [").collect::<Vec<&str>>()[0],&buffer.replace(" ", "\n"),std::fs::read_to_string(&args[1]).expect("cant open new configuration").split("environment.systemPackages = with pkgs;\n  [").collect::<Vec<&str>>()[1])).expect("cant write into new configuration");
+```
+This is the fun part!
+so, we use write!() to write the new, modified configuration into `newConfiguraiton.nix` this file is created in here immediatly with `std::fs::File::creat("newconfiguration.nix)` <br>
+The whole contents are also created on the fly inside of `write!()` with `format!()`<br>
+First we read the user specified file into a string, immediatly split it at `environment.systemPackages = with pkgs;\n  [` and write the first part of this new, splitted string <br>
+then we add `environment.systemPackages = with pkgs;\n  [` again, since the `.split()` seems to remove that part<br>
+after that we add the `buffer` variable, which contains all the packages, but replace spaces with "\n" so that each package is in its own line <br>
+then we split the user specified configuartion again, but this time we add the second part of the splitted file<br>
+<br>
+```rust
+Ok(()) }
+```
+To be honest, I dont really know what `Ok(())` does, all I know is that its needed when the function is expected to return status stuff
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