Minishell

ℹ️ About The Project

42 Project

We were asked to make our own shell, replicating basic functionalities. Everything was coded in C, respecting Norminette code convention.

Subject

• Subject

Architecture

• Tokenize: builds the Command Table (simple commands, IO files) from command line input. Handles input syntax errors.
• Executor: redirects IO and creates pipes if needed. Forks if launching an executable. Handles built-in commands errors.

Bash Peculiarities

• We don't have a MULTIOS option enabled by default, as is the case in zsh.

Allowed Functions

Expand

• malloc
• free
• write
• open
• read
• close
• fork = Creates a child process. Why is fork used?
• wait = Stops the parent process until the child process exit.
• waitpid = The waitpid() function shall be equivalent to wait() if the pid argument is (pid_t)-1 and the options argument is 0. Otherwise, its behavior shall be modified by the values of the pid and options arguments.
• wait3, wait4 = Obsolete.
• signal = Sets a function to handle a signal.
• kill = Sends a signal to a process or a group of processes.
• exit = Terminates a process immediately, special handle for child processes.
• getcwd = Saves the pathname of your current working directory in a string.
• chdir = Changes your current working directory.
• stat, lstat, fstat = Returns information about a file.
  • stat = Standar.
  • lstat = For symbolic links.
  • fstat = Gets the file from a file descriptor.
• execve = Executes a program referred by a variable. (How to use)
• dup = Creates a copy of a file descriptor using the lowest numbereded unused descriptor.
• dup2 = Creates a copy of a file descriptor using the descriptor number given by the user.
• pipe = It's used to create inter-process communication. Interface in minishell?
• opendir = Opens a directory stream.
• readdir = Returns a pointer to a dirent structure representing the next directory entry in the directory stream.
• closedir = Closes the directory stream.
  • opendir, readdir, closedir example here
• strerror = Returns an error message.
• errno = Number of last error, its a variable.

(back to top)

🏃 Quick Start

Important

• Project has only been tested and runned on macOS systems

Installation

• Clone the repo

  git clone https://github.com/its-a-maxi/minishell.git

(back to top)

⌨️ Usage

• Compile

  make

• Run minishell

  ./minishell

(back to top)

📫 Contact

Maximo Monroy - monroy.vds@gmail.com

Alejandro León - https://github.com/ElHuaco

Project Link: https://github.com/its-a-maxi/minishell

(back to top)

🥇 Acknowledgments

• There is a github repository that obeys the order of proceedings pretty nicely.
• Please make sure to do a lexer -> parser -> expander -> executor to make your life easier. Here is a solid start.
• Make sure that you understand the shell syntax
• Making your own shell
• Subject
• A reference.
• Another one.
• Use of **envp in main
• Pipe and redirection algorithm for A|B|C|D > outfile < infile

(back to top)