Rust‑Powered Shell (rspwsh)

A lightning‑fast, object‑aware command‑line shell written from scratch in Rust. This README corresponds to the repository KartikDua1504/Powershell.

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1 · Quick Install

# prerequisite: Rust ≥ 1.77 (install with rustup if missing)

# clone *this* repo
 git clone https://github.com/KartikDua1504/Powershell.git
 cd Powershell

# build an optimised release binary
 cargo build --release        # ≈ 20 s on a recent laptop

# (optional) move it onto $PATH so you can call it from anywhere
 sudo mv target/release/rspwsh /usr/local/bin

# launch an interactive session
 rspwsh

Run a one‑shot command and exit:

rspwsh -c "echo 'hello world'"

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2 · Everyday Usage

Task	Example
Change directory	cd ~/projects
Install a package	sudo dnf install ripgrep
List only large files	`ls	where size > 10MB`
Search command history	history -p make
Exit the shell	exit or Ctrl+D

Shortcuts – Tab = autocomplete · Ctrl+R = reverse search · Ctrl+C = cancel · Ctrl+L = clear.

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3 · How It Works (Bird’s‑Eye View)

+-----------+           +-------------------+
| main.rs   |──► input │  command::parser  │  ➜ AST
+-----------+           +-------------------+
                                │
                                ▼
                        +-------------------+
                        │  shell::exec      │  built‑in? spawn?
                        +-------------------+
                                │
                                ▼
                        +-------------------+
                        │ trie::autocomplete│  Tab suggestions
                        +-------------------+

• Zero unsafe code – memory safety throughout.
• termion – raw‑mode terminal handling and key events.
• serde – stream JSON/CSV as rich objects between commands.
• anyhow / thiserror – ergonomic error propagation.

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4 · Extending rspwsh

Adding a built‑in command is a two‑step affair:

struct Greet;
impl BuiltIn for Greet {
    fn name(&self) -> &'static str { "greet" }
    fn execute(&self, args: &[String]) -> Result<i32, ShellError> {
        println!("Hello, {}!", args.get(0).unwrap_or(&"world".into()));
        Ok(0)
    }
}

Register it in shell/mod.rs:

builtins.insert("greet", Box::new(Greet));

Re‑compile (cargo build --release) and the command is live—complete with autocomplete and help support.

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5 · Troubleshooting

Symptom	Remedy
Binary won’t execute	Build directly on the target machine or use correct --target.
Prompt lacks colour	Ensure $TERM supports ANSI (e.g. xterm-256color).
Slow autocomplete (first run)	Trie builds once; subsequent sessions are instant.

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