https://github.com/msaf9/custom-shell
The shell supports fundamental features such as executing commands, handling background processes using &, and enabling input/output redirection with < and >. Additionally, it supports piped commands (|) to facilitate command chaining.
https://github.com/msaf9/custom-shell
c-programming-language shell
Last synced: 2 months ago
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The shell supports fundamental features such as executing commands, handling background processes using &, and enabling input/output redirection with < and >. Additionally, it supports piped commands (|) to facilitate command chaining.
- Host: GitHub
- URL: https://github.com/msaf9/custom-shell
- Owner: msaf9
- License: mit
- Created: 2025-02-02T05:45:54.000Z (4 months ago)
- Default Branch: main
- Last Pushed: 2025-02-07T21:56:04.000Z (4 months ago)
- Last Synced: 2025-02-07T22:34:06.783Z (4 months ago)
- Topics: c-programming-language, shell
- Language: C
- Homepage:
- Size: 15.6 KB
- Stars: 0
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# Custom Shell
Designed to provide a lightweight yet functional command-line interface.
## Table of Contents
- [Overview](#overview)
- [Features](#features)
- [1. Command Execution](#1-command-execution)
- [2. Background Execution](#2-background-execution)
- [3. Input and Output Redirection](#3-input-and-output-redirection)
- [4. Piped Commands](#4-piped-commands)
- [5. Built-in Commands](#5-built-in-commands)
- [Compilation and Execution](#compilation-and-execution)
- [Compiling the Shell](#compiling-the-shell)
- [Running the Shell](#running-the-shell)
- [Usage](#usage)
- [Code Structure](#code-structure)
- [Files](#files)
- [Functions](#functions)
- [Example Commands](#example-commands)
- [Limitations](#limitations)
- [Future Enhancements](#future-enhancements)
- [License](#license)
## Overview
This project is a simple custom shell implemented in C. The shell supports various features such as:
- Command execution
- Background execution using `&`
- Input redirection using `<`
- Output redirection using `>`
- Piped commands using `|`
- Built-in commands: `cd`, `exit`, and `history`
- Command history tracking
- Re-execution of commands from history using `!`
## Features
### 1. Command Execution
The shell allows users to execute standard shell commands by typing them into the prompt.
### 2. Background Execution
Appending `&` to a command runs it in the background.
### 3. Input and Output Redirection
- `< filename` redirects input from a file.
- `> filename` redirects output to a file.
### 4. Piped Commands
The shell supports multiple piped commands (e.g., `ls | grep txt`).
### 5. Built-in Commands
- `cd `: Changes the current working directory.
- `exit`: Exits the shell.
- `history`: Displays a list of previously executed commands.
- `!`: Re-executes a command from history.
## Compilation and Execution
### Compiling the Shell
```sh
gcc src/Shell.c -o Shell
```
### Running the Shell
```sh
./Shell
```
## Usage
1. Run the shell using `./mysh`.
2. Enter commands at the `mysh>` prompt.
3. Use built-in commands as needed.
4. Use `CTRL+C` to terminate a running foreground process.
## Code Structure
### Files
- `shell.c`: Main source file for the shell implementation.
- `shell.h`: Header file containing function declarations and constants.
- `Makefile`: Automates the build process.
### Functions
- `add_to_history`: Stores commands in history.
- `print_history`: Displays command history.
- `parse_input`: Splits input into commands, supporting pipes.
- `parse_command`: Parses a command, handling arguments and redirections.
- `execute_command`: Runs a command with optional redirection.
- `execute_piped_commands`: Executes a sequence of piped commands.
- `handle_builtin`: Processes built-in commands like `cd`, `exit`, and `history`.
- `main`: Main loop handling user input and executing commands.
## Example Commands
```sh
mysh> ls -l
mysh> echo "Hello World" > output.txt
mysh> cat < output.txt
mysh> history
mysh> !2 # Re-executes the second command from history
mysh> ls | grep .c
mysh> sleep 5 & # Runs in the background
```
## Limitations
- No advanced error handling for deeply nested pipes.
- Limited support for environment variable expansion.
- No tab-completion or advanced interactive features.
- Background processes do not support job control.
## Future Enhancements
- Implement environment variable support.
- Add tab-completion.
- Improve error handling and reporting.
- Support job control for background processes.
## License
This project is released under the [MIT License](LICENSE).