freSH

freSH (FRiendly Easy SHell) is a simple, interactive command-line shell written in Rust. It aims to provide a user-friendly shell experience with essential features such as command execution, history management, and support for pipelines, all in a lightweight and modern Rust codebase.

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Overview

freSH is designed as a minimal yet functional shell for Unix-like systems. It provides a familiar shell prompt, supports running external commands, handles basic shell built-ins like cd and exit, and allows users to chain commands using pipelines (|). Command history is persisted across sessions for convenience.

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Features

• Interactive Shell Prompt Presents a prompt for user input, with a welcoming ASCII art banner.

• Command Execution Runs external commands with arguments, just like a typical shell.

• Built-in Commands

  • cd <dir>: Change the current working directory.
  • exit: Exit the shell gracefully.

• Pipelines Supports chaining commands using the pipe (|) operator, passing the output of one command as the input to the next.

• Command History Remembers previously entered commands across sessions using a persistent history file (/tmp/.fresh_history).

• Graceful Exit Handles Ctrl-C and Ctrl-D to exit cleanly, saving command history.

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Getting Started

Prerequisites

• Rust (edition 2024 or later)

Build and Run

git clone https://github.com/vrn21/fresh
cd fresh
cargo run

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Usage

• Type any command and press Enter to execute.
• Use cd <directory> to change directories.
• Use exit or press Ctrl-D/Ctrl-C to quit.
• Chain commands with | for pipelines, e.g.:

  ls -l | grep ".rs" | sort
  

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Architecture

Main Components

• Entry Point (main.rs) The shell starts by displaying an ASCII art banner and a welcome message. It initializes a line editor using the rustyline crate for interactive input and history management.

• Event Loop The shell enters a loop, prompting the user for input. For each line:

  • If the input is empty, it prompts again.
  • If the input is exit, the shell exits.
  • If the input is cd <dir>, it changes the current directory.
  • Otherwise, it parses the input for pipelines (|), splits the command, and executes each segment, connecting their input/output as needed.

• Command Execution Uses Rust's std::process::Command to spawn child processes for each command. Handles standard input/output redirection for pipelines.

• History Management Loads command history from /tmp/.fresh_history at startup and saves it on exit or interruption.

• Error Handling Prints errors to standard error if command execution fails or if built-in commands encounter issues.

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Dependencies

• rustyline — For interactive input and history.

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License

This project is licensed under the MIT License.

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freSH is a learning project and a foundation for building more advanced shell features in Rust. Contributions and suggestions are welcome!