Minishell is a core project from the 42 curriculum that replicates the behavior of a simplified Unix shell. It aims to deepen your understanding of process management, file descriptors, signals, parsing, and job control by building your own command-line interpreter from scratch in C.

• 🧠 Custom shell parsing and syntax handling
• 📜 Support for sequential and piped command execution
• 🪄 Built-in commands: cd, echo, env, exit, export, pwd, unset, history
• 🌍 Environment variable management and expansion ($VAR support)
• 🧱 Redirections: input <, output >, append >>, and heredocs <<
• 🔗 Full support for pipelines using |
• 🧼 Proper memory and file descriptor management
• 📶 Signal handling: handles EOF (ctl+D), SIGINT (Ctrl+C) and SIGQUIT (Ctrl+\) gracefully
• 🧵 Forking and process execution with correct exit codes
• 🧪 Error handling for syntax errors and "command not found"
• 🔄 Command history persistence across sessions
• 🧠 Advanced quoting, escaping, and syntax error detection
• 🪄 Auto-completion support (via readline hooks)
• 📜 Custom shell prompt

• Parse and execute commands using fork() and execve()
• Wait for child processes using wait() / waitpid() and return correct exit statuses
• Execute piped commands by managing file descriptors correctly

• Split and analyze user input: detect pipes, redirections, quotes, and variable expansions
• Respect shell grammar: handle nested quotes (', ") and escape characters
• Handle empty inputs and multiple spaces or tabs gracefully

• echo [-n] — Print arguments
• cd [dir] — Change current directory
• pwd — Print working directory
• export VAR=val — Set environment variable
• unset VAR — Remove variable
• env — List environment variables
• history — Show command history for the current session
• exit [code] — Exit the shell with an optional status code

• > — Redirect output (overwrite)
• >> — Redirect output (append)
• < — Redirect input
• << — Heredoc input until limiter is found

• Handle $VAR expansion from the current environment and local variables
• Expand variables inside double quotes ", but not inside single quotes '

• Ctrl+C (SIGINT) — Interrupts current input line without exiting
• Ctrl+\ (SIGQUIT) — Ignored in the main shell, passed to child processes like in Bash
• Ctrl+D (EOF) — Exits the shell if the input line is empty (end-of-file condition)

• ❌ No use of system(), printf(), or external parsing libraries

• ✅ Must use readline for line input and command history

• 📁 No memory or file descriptor leaks (must pass valgrind or leaks)

• 🔀 Code must comply with 42 Norminette:

  • Maximum 25 lines per function
  • Maximum 4 variables per function
  • Maximum 4 arguments per function

To compile the project, simply run:

make

This will generate the minishell executable.

Start your shell with:

./minishell

You'll be greeted with a custom prompt where you can type commands just like in Bash.

• Use up/down arrows to navigate command history
• Chain commands using pipes (|)
• Redirect output and input using >, >>, <, and <<
• Use Ctrl+C to cancel a running foreground command
• Type exit to quit the shell

zmbash-2.5$ echo hello | cat -e
hellozmbash-2.5$

zmbash-2.5$ export NAME=world
zmbash-2.5$ echo $NAME
world
zmbash-2.5$

zmbash-2.5$ ls > out.txt
zmbash-2.5$ cat < out.txt | grep .c
main.c
utils.c
zmbash-2.5$