https://github.com/magalhaesm/minishell
This project is about creating a simple shell.
https://github.com/magalhaesm/minishell
42saopaulo 42school 42sp c ecole42 makefile minishell minishell-42 minishell42
Last synced: about 1 month ago
JSON representation
This project is about creating a simple shell.
- Host: GitHub
- URL: https://github.com/magalhaesm/minishell
- Owner: magalhaesm
- License: gpl-3.0
- Created: 2022-10-26T11:41:07.000Z (almost 3 years ago)
- Default Branch: main
- Last Pushed: 2024-06-06T17:22:16.000Z (over 1 year ago)
- Last Synced: 2025-08-23T18:58:34.514Z (about 1 month ago)
- Topics: 42saopaulo, 42school, 42sp, c, ecole42, makefile, minishell, minishell-42, minishell42
- Language: C
- Homepage:
- Size: 256 KB
- Stars: 3
- Watchers: 1
- Forks: 1
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
## Introduction
The 8th project of 42 cursus syllabus asks students to implement a simplified shell. It's about minishell, as beautiful as a shell.
As the project's subject states, the existence of shells is linked to the very existence of IT. At the time, all developers agreed that _communicating with a computer using aligned 1/0 swiches was seriously irritating_. It was only logical that they came up with the idea of creating a software to communicate with a computer using interactive lines of commands in a language somewhat close to the human language.
## How to compile and run the project
#### 1) Copy this repository to your local workstation
```html
git clone https://github.com/magalhaesm/minishell.git
```
#### 2) Install the required libraries to run the functions from readline library
```html
sudo apt-get install -y libreadline6 libreadline6-dev
```
#### 3) Compile the project with Makefile
```html
make
```
#### 4) Launch the executable file
```html
./minishell
```
If you want to run the executable program automatically with valgrind flags to check for leaks, just write `make checks` and press enter.
## Implemented builtins
| Builtin | Command description |
|:------|:------|
| `echo` with `-n` | Displays a line of text to the standard output |
| `cd` | Changes the working directory of the current shell execution environment |
| `pwd` | Prints the full filename of the current working directory |
| `export name[=word]` | Sets the export attribute for variables |
| `unset` | Unsets values and attributes of variables and functions |
| `env` | Sets each name to value in the enviroment and run command |
| `exit` | Causes the shell to exit with exit status specified |
## About how we implemented the project
There are two main files at projects's root directory:
- `include`: contains all the necessary headers for the project
- `grammar`: the implemented grammar, which creates and checks the sentences
- `libft`: our own C library with some helpful auxiliary functions, such as ft_strlen
- `tests`: contains unit tests created with [Criterion](https://github.com/Snaipe/Criterion) testing framework to evaluate functions in `src`
- `src`: contains the whole project implementation
- `builtins`: implements the required builtins by the project's subject
- `exec`: consists of functions that executes user's input
- `expansion`: implements shell expansors, such as quote marks and wildcards
- `helpers`: contains utils function used on the project as a whole
- `parser`: consists of functions that implement the minishell's grammar and create a tree of a given input by the user
- `scanner`: implements a scanner to create tokens of a given input by the user
- `signals`: consists of functions that handle user events, such as `ctrl-C`, `ctrl-D` and `ctrl-\`
- `table`: implements a hash table to store enviroment variables
## Project flowchart
In a nutshell, the project flowchart is as follows:
```mermaid
graph LR;
INPUT-->scanner;
scanner-->parser;
parser-->expansor;
expansor-->executor;
executor-->OUTPUT
```
As an example, if given the input `true && ls || echo` the program generates the tree below to be executed:
```mermaid
graph TD;
OR-->AND;
OR-->echo;
AND-->true;
AND-->ls;
```
## References
- General references:
- [CS 61: Systems Programming and Machine Organization (2022)](https://cs61.seas.harvard.edu/site/2022/#gsc.tab=0), by Harvard University
- NYSTROM, Robert. _Crafting interpreters_. 2020
- AHO, Alfred. _Compiladores: princípios, técnicas e ferramentas_. 2007
- [Playlist about compilers](https://www.youtube.com/playlist?list=PLX6Nyaq0ebfhI396WlWN6WlBm-tp7vDtV), by [Judson Santiago](https://www.youtube.com/@JudSan)
- [Playlist about Programming Languages and Compilers](https://www.youtube.com/playlist?list=PLvat2X-KHJNYmC4M1HHrDkMkFDf8Dwyf8), by [Rafael Ivo](https://www.youtube.com/@ProfessorRafaelIvo)
- [Subshell: types and origins](https://www.youtube.com/watch?v=MkejZKVfsRg), by [prog.shell.linux](https://www.youtube.com/@progshelllinux)
- Useful tools for grammar generation:
- [The context free grammar checker](https://smlweb.cpsc.ucalgary.ca/start.html), by [University of Calgary](https://science.ucalgary.ca/computer-science)
- [Grammophone: transform context-free grammars](https://mdaines.github.io/grammophone/)
- About hash table implementation
- [FNV Hash](http://www.isthe.com/chongo/tech/comp/fnv/#FNV-1a), by [Landon Curt Noll](http://www.isthe.com/chongo/index.html)
- About parser:
- [Recursive Descendant Parsing](https://www.youtube.com/watch?v=SToUyjAsaFk), by [hhp3](https://www.youtube.com/@hhp3)
- About syntax analyzer:
- [08: Análise Sintática Top Down: Parser Descendente Recursivo](https://www.youtube.com/watch?v=dvql913QHzs) and [10: Análise Preditiva (Parser Recursivo Preditivo](https://www.youtube.com/watch?v=8nb-6Zo_X_0), by [Andre Du Bois](https://www.youtube.com/@andredubois7117)
- About bonus implementation
- [Wildcard Matching with Dynamic Programming](https://www.youtube.com/watch?v=3ZDZ-N0EPV0), by [Tushar Roy](https://www.youtube.com/@tusharroy2525)
- The same project done by fellows 42SP's students
- https://github.com/sgkhusal/minishell/
- https://github.com/SouzaSA/42sp_minishell.git
- Automated tester that helped us to find some bugs:
- https://github.com/LucasKuhn/minishell_tester