#minishell
🚀 This project was one of the most challenging yet rewarding experiences in the 42 curriculum. It involved handling numerous test cases and learning a wide range of topics, from software architecture and system calls to team coordination and task distribution.
⚡ Initially, building a shell that mimics Bash seemed intimidating. Our prior knowledge of shells was limited to basic usage, and we had no idea how they worked internally.
➥ Creating a shell from scratch was a significant challenge, but it highlighted one of the core aspects we love about the 42 pedagogy: constantly facing new challenges and learning opportunities, from the early days of the Piscine (42 selection phase) up to now.
💥 Minishell is a substantial project, especially for beginners, and it required careful planning and research to avoid major redesigns later—although We still ended up making significant changes.
👩🏻💻🧑🏻💻 Since this was a team project, We needed to find a partner. After forming a team of two, we started coordinating tasks and working together.
🛑 The shell has two main parts: parsing (processing user input) and execution (running the parsed commands). Through this project, We not only improved my technical skills but also learned valuable lessons in teamwork and project management.
#</> Anyway, let’s have a project overview…
✔ We are required to build a mini shell (command-line interpreter) that mimics the bash, hence the name it wouldn’t be doing all the work that bash does, but the basic functionality:
► The shell will work only in interactive mode (no scripts, i.e. the executable takes no arguments)
► Run simple commands with absolute, relative path (e.g. /bin/ls, ../bin/ls)
► Run simple commands without a path (e.g. ls, cat, grep, etc…)
► Have a working history (you can navigate through commands with up/down arrows)
► Implement pipes (|)
► Implement redirections (<, >, >>)
► Implement the here-doc (<<)
► Handle double quotes ("") and single quotes (''), which should escape special characters, beside $ for double quotes.
► Handle environment variables ($ followed by a sequence of characters).
► Handle signals like in bash (ctrl + C, ctrl + \, ctrl + D).
#👉🏼Implement the following built-ins:
➜ echo (option -n only)
➜ exit
➜ env (with no options or arguments)
➜ export (with no options)
➜ unset (with no options)
➜ cd
➜ pwd
#⚠And for the bonus part (optional, for us we didn't do it)
➤ handle && and || with the parenthesis () for priority.
➤ handle * wildcards for the current working directory.
#😵💫OMG! Where to start?! That was our reaction when we first read the assignment.
After researching how Bash works, We discovered that its implementation is divided into two main parts:
#🌟 Handles user input and interaction, such as commands and signals.
#🌟 Manages the execution of commands.
◼ In the first part, we need to handle two main things: commands (user input as text) and signals (like Ctrl+C).
◼ We decided to focus on handling user input first and postpone signal handling to avoid unnecessary complexity at the start.
✏️ Our first task was to figure out how the shell processes user input. We realized there must be a systematic way to handle these lines. Many of our peers were tempted to hard-code the parsing and handle cases naively.
𑁍We felt the same temptation but chose to step out of our comfort zone and learn something new.
╰┈➤By taking this approach, We aimed to create a more robust and flexible shell, gaining deeper insights into how shells work and improving our programming skills along the way.
