A Complete Minishell

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🐚 General information

Version: 6. Bonus included.
Compliant with the new rules in version 6.1. about using global variables only for signals.
Built with the latest bash version: GNU bash, version 5.2.21(1)-release (x86_64-apple-darwin19.6.0).
Made by Florent & Ulysse

🚀 Set-up

To keep the GitHub repository tidy and to avoid displaying library code, the lib directory is archived. Follow the steps below to set up and run the project:

1. Decompress the Libraries: tar xzf lib.tar.gz && rm -rf lib.tar.gz
   If needed, to re-archive: tar czf lib.tar.gz lib/ && rm -rf lib/
2. Install readline library via homebrew: brew install readline
3. Compile the Project: make
4. Run the Project: ./minishell

✨ What makes this minishell special?

• Fidelity: built directly on the bash manual and some POSIX standards.
• Robustness: the Recursive descent parser allows to handle complex commands.
• Extensibility: thanks to the Abstract Syntax Tree execution, it is easy to add new features.
• Performance: to avoid unnecessary search, binaries paths are cached in memory (see /src/get_bin_path.c). We also use recursion for parsing and execution.
• Security: robust design, all system calls checked.
• Documentation: parts of the code is documented with doxygen style. The /docs/ directory include EBNF-like grammar, adapted bash manual and some other resources.
• Debugging: tokens from the lexer and ast nodes from the parser can be printed in json format (see /src/debug.c) and displayed here.
• Bonuses:
  • Parenthesis are implemented as subshells for easier testing.
  • Wildcard are working for simple subdirectories (e.g. ls src/*).

⚠️ Limitations

• Newline and semicolon separators are not implemented; therefore, only one command per input line is supported. New lines in user input can lead to undefined behavior.
• Known bugs:
  • (>out): return a syntax error but shouldn't.
  • ls random_dir/*: display well the error but also exit the minishell.

📚 Documentation & Resources

• resources.md
• bash_manual_for_minishell.md
• grammar.md: EBNF-like grammar
• notes_for_evaluation.md: Implementation Choices + KO tests and reasons
• subject.md + subject_prompt_for_llm.md

🚴‍♂️ Advices to succeed Minishell project

• Learn what bash, a POSIX shell, and a terminal are, and understand the differences between these concepts.
• Read the entire bash manual (it's shorter than it looks) or our truncated version in /docs/bash_manual_for_minishell.md.
• "bash manual > bash testing". Of course I highly recommend to test bash to understand it, but often taking a test instead of using the manual as a reference can be misleading.
• Use AST, it's a bit more complicated at first glance, but it will make your life much easier later on.
• USE TESTERS !!!

📋 Testing

We use the two testers below. The docs/Notes_for_evaluation.md details each KO test and reasons (most of them are considered out of scope).

• /mpanic : [549 OK]
• /42_minishell_tester : [2935 OK]