minishell

What is this?

This is our take on the 42 minishell project: a small Unix-like shell built in C.

This project was developed by:

d3bvstack

marcogmurciano

The goal was not to clone Bash 1:1, but to build a shell that feels real in day-to-day use: run commands, chain programs with pipes, redirect input/output, use environment variables, handle signals properly, and support the essential builtins you expect.

If libft was about learning C fundamentals, minishell is where everything starts to click together: parsing, process management, file descriptors, signals, and error handling all in one place.

What can this minishell do?

At a high level, you can:

• Run external commands from PATH or by direct path (/bin/ls, ./my_program)
• Chain commands with pipes (|)
• Redirect input/output with <, >, >>
• Use heredoc (<<) to feed multiline input
• Expand environment variables ($HOME, $USER) and last exit code ($?)
• Work with single and double quotes
• Use core builtins to navigate and manage your environment
• Handle Ctrl+C and Ctrl+\ in a shell-appropriate way

In short: enough to feel like a real shell while staying within minishell scope.

Builtins included

• echo with -n flag
• cd
• pwd
• export
• unset
• env
• exit

What this project covers (learning-wise)

This project forced me to connect several core systems topics:

• Tokenizing and parsing user input into executable structures
• Building and executing pipelines across multiple processes
• Managing redirections and heredoc safely
• Tracking and propagating exit statuses
• Coordinating parent/child signal behavior
• Maintaining environment state between commands
• Cleaning up memory and resources in long-running interactive loops

What this minishell does not try to be

This is a pedagogical shell, not a full Bash replacement.

So things like advanced Bash features are out of scope here (for example: &&, ||, command substitution, wildcards/globbing, job control, aliases, etc.).

Build and run

From the project root:

make
./bin/minishell

Useful targets:

make clean
make fclean
make re

Project structure (quick view)

• src/tokenization: splits raw input into tokens
• src/syntax: builds command structures and validates syntax
• src/expansion: handles $VARIABLE and $? expansion
• src/execution: runs commands, pipelines, redirections, heredoc logic
• src/builtins: shell builtins
• src/signals: interactive signal behavior
• src/environment: environment list/array management

Final note

This project is where "I know C syntax" turns into "I can build systems software with C".

It is opinionated, scoped, and intentionally not everything under the sun, but it covers the heart of what makes a shell a shell.