Minishell is a 42 school team project to create a basic shell program in C. It implements redirections and pipes, as well as environment variable expansions and the cd, echo, env, exit, export, pwd and unset builtin commands.

Validated 11/11/2022. Grade: 99%.

Clone the repository with the minitester submodule:

git clone --recurse-submodules [email protected]:mcombeau/minishell.git

To compile:

cd minishell && make

To run the program:

./minishell

A prompt will appear. You may enter your commands to be executed.

To run the included tester:

cd minitester/ && bash minitester.sh

Minishell is a miniature shell program based on Bash. Minishell supports:

• Prompt display
• Command history (up and down arrows)
• System executables available from the environment (ls, cat, grep, etc.)
• Local executables (./minishell)
• Builtin commands :
  • echo (and option -n)
  • cd (with only a relative or absolute path)
  • pwd (no options)
  • export (no options)
  • unset (no options)
  • env (no options or arguments)
  • exit (with exit number but no other options)
• Pipes | which redirect output from one command to input for the next
• Redirections:
  • > redirects output
  • >> redirects output in append mode
  • < redirects input
  • << DELIMITER displays a new prompt, reads user input until reaching DELIMITER, redirects user input to command input (does not update history)
• Environment variables (i.e. $USER or $VAR) that expand to their values.
  • $? expands to the exit status of the most recently executed foreground pipeline.
• User keyboard signals:
  • ctrl-c displays a new prompt line.
  • ctrl-d exits minishell
  • ctrl-\ does nothing

However, Minishell does not support \, ;, &&, ||, or wildcards.

🇺🇸 Articles in English about the concepts tackled in this project:

• Creating and Killing Child Processes in C
• Pipe: an Inter-Process Communication Method
• Sending and Intercepting a Signal in C
• Handling a File by its Descriptor in C
• Errno and Error Management in C

🇫🇷 Articles en français sur les concepts abordés dans ce projet :

• Créer et tuer des processus fils en C
• Pipe : une méthode de communication inter-processus
• Envoyer et intercepter un signal en C
• Manipuler un fichier à l’aide de son descripteur en C
• Errno et la gestion d’erreur en C

Other useful links:

• Bash reference manual
• Introduction to Systems Programming: a Hands-on Approach, Chapter 5. Writing Your Own Shell
• Stephen Brennan's Tutorial - Write a Shell in C
• The Open Group Base Specifications, Shell Command Language
• A Guide to Unix Shell Quoting
• Austin Tripp's Quick Tutorial on Bash Quotes

Made by aquesada and mcombeau