A simple shell command interpreter

This project is part of the ALX Software Engineering program - Low level programming part. In this project, we will implement a simple shell based on csh and using C89. Our shell will:

• Display a prompt and wait for the user to type a command. A command line always ends with a new line.
• The prompt is displayed again each time a command has been executed.
• Support command with multiple arguments.
• The command lines handles semicolons, &&, and ||
• No pipes, no redirections or any other advanced features.
• If an executable cannot be found, print an error message and display the prompt again.
• Handle errors.
• Handle the “end of file” condition (Ctrl+D)
• Implement some builtins cd, wait, env, setenv, unsetenv, alias.
• Support comments.
• can be run as in interactive and non interactive mode (passing shell script as argument).

• getline
• Path handling.
• strdup`
• realloc`
• strtok
• puts
• strlen
• strcmp
• strncpy
• strcat

• Allowed editors: vi, vim, emacs
• All your files will be compiled on Ubuntu 20.04 LTS using gcc, using the options -Wall -Werror -Wextra -pedantic -std=gnu89
• All your files should end with a new line
• A README.md file, at the root of the folder of the project is mandatory
• Your code should use the Betty style. It will be checked using betty-style.pl and betty-doc.pl
• Your shell should not have any memory leaks
• No more than 5 functions per file
• All your header files should be include guarded
• Use system calls only when you need to why?
• Write a README with the description of your project
• You should have an AUTHORS file at the root of your repository, listing all individuals having contributed content to the repository.

• access (man 2 access)
• chdir (man 2 chdir)
• close (man 2 close)
• closedir (man 3 closedir)
• execve (man 2 execve)
• exit (man 3 exit)
• _exit (man 2 _exit)
• fflush (man 3 fflush)
• fork (man 2 fork)
• free (man 3 free)
• getcwd (man 3 getcwd)
• getpid (man 2 getpid)
• isatty (man 3 isatty)
• kill (man 2 kill)
• malloc (man 3 malloc)
• open (man 2 open)
• opendir (man 3 opendir)
• perror (man 3 perror)
• read (man 2 read)
• readdir (man 3 readdir)
• signal (man 2 signal)
• stat (__xstat) (man 2 stat)
• lstat (__lxstat) (man 2 lstat)
• fstat (__fxstat) (man 2 fstat)
• wait (man 2 wait)
• waitpid (man 2 waitpid)
• wait3 (man 2 wait3)
• wait4 (man 2 wait4)
• write (man 2 write)