Minishell – Unix Shell Implementation in C

Minishell is a Unix shell implementation written in C as part of the 42 School curriculum. It reproduces core Bash behaviors including command execution, pipelines, redirections, environment variable expansion, built-in commands, and signal handling. The project focuses on process management, file descriptor manipulation, parsing logic, and system-level programming concepts.

Overview

• Language: C
• Architecture: Modular parsing and execution pipeline
• Process Handling: fork, execve, wait
• Inter-process Communication: pipes
• File Descriptor Management: dup2, redirections
• Environment Handling: variable expansion and export management
• Signal Handling: ctrl-c, ctrl-d, ctrl-\
• Focus: Low-level Unix systems programming

Supported features

• 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.

Installation

git clone <repository_url>
cd minishell
make

Usage

./minishell (anything from listed above)

Exemple

./minishell cat Makefile | grep o > out