📟 minishell

Score	Duration	Peer(s)
✅ 125 / 100	🕓 8 week(s)	👷🏻 Yes

This team project is a program that reproduces the bash shell. It includes prompt, persistent history, several builtins, full support for quotes (double and single), redirections and piping, shell variables and environment variables and their expansion, signal processing, support for logical operators, subshells and wildcards.

📋 Table of contents

• 👀 Overview
• 📦 Requirements
• 💾 Installation
• ⚡️ Usage
• 🛠️ Makefile
• 📄 License

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👀 Overview

General

• Display a prompt while waiting for an input.
• Search order for binaries identical to bash.
• Executes the correct binaries.

History

• Supports session history.
• Supports persistent history (file storage).

Builtins

• Implements builtins echo, cd, pwd, export, unset, env and exit.

Quotes

• Supports simple quotes '' and double quotes "".
• Supports unclosed double quotes.
• Supports unclosed simple quotes.

Redirections

• Supports pipe | redirections.
• Supports <, > and >> file redirections.
• Supports heredoc << redirections.
• Supports herestring <<< redirections.

Variables

• Supports environment variables.
• Supports shell variables.
• Shell variables can be exported with export.
• Supports variable $?.

Signals

• Supports signals CTRL-C, CTRL-D and CTRL-\ in passive and interactive mode.

Operators

• Supports logical operators && and ||.

Subshell

• Supports the execution of subshells in parentheses ().

Delimiters

• Supports token ; as delimiter.
• Supports incomplete lines ending with |, && or ||.

Wildcard

• Supports wildcard * in the basename of any absolute or relative path.

Comments

• Supports inline comments with token #.

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📦 Requirements

sudo apt -y install clang-12 make libreadline-dev

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💾 Installation

1. Get the project

git clone https://github.com/Vlad-PLK/MINISHELL.git

2. Build the project

make -j$(nproc)

🔵 Info: The minishell executable will be created in the project root directory.

3. Run the project

./minishell

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⚡️ Usage

Double quotes:

minishell$ echo "Like a shell: $SHELL"
Like a shell: 42-minishell/minishell

Simple quotes:

minishell$ echo 'Like a shell: $SHELL'
Like a shell: $SHELL

Unclosed quotes:

minishell$ echo "Hello 
> world!"
Hello 
world!

Pipe redirection:

minishell$ echo "Hello world!" | cat --number
     1  Hello world!

File redirection:

minishell$ echo "Hello world #1" > a.txt
minishell$ echo "Hello world #2" >> a.txt
minishell$ cat --number < a.txt
     1  Hello world #1
     2  Hello world #2

Heredoc:

minishell$ cat << DEL
> Hello
> world!
> DEL
Hello 
world!

Herestring:

minishell$ cat <<< "Hello world!\n"
Hello world!

Environment variables:

minishell$ export A="Hello world!"; echo $A
Hello world!

Shell variables:

minishell$ A="Hello world!"; echo $A
Hello world!

Logical operators:

minishell$ echo "A" && echo "B" || echo "C" && echo "D"
A
B
D

Subshell:

minishell$ echo "A" && echo "B" || (echo "C" && echo "D")
A
B

Delimiters:

minishell$ echo Hello; echo world!
Hello
world!

Incomplete lines:

minishell$ echo "Hello world!" |
> wc -w
2

minishell$ echo -n "Hello " &&
> echo "world!"
Hello world!

minishell$ echo "Hello " ||
> echo "world!"
Hello

Wildcards:

minishell$ echo includes/m*.h
includes/minishell.h

Comments:

minishell$ echo "Hello world!" # It's an inline comments!
Hello world!

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🛠️ Makefile

Rule	Action
all	Compile.
clean	Delete all generated object files
fclean	Apply clean, lcleanand delete the executable.
lclean	Apply fclean to all used libraries.
re	Apply fclean and force recompile.

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