Write a simple UNIX command interpreter A simple shell command written in C-lang
this project is a simple UNIX command interpreter that replicates functionalities of the shell. However, the whole of this project is written in the C programming language for ALx Holberton Software Engineering School
- Who designed and implemented the original Unix operating system
- Who wrote the first version of the UNIX shell
- Who invented the B programming language (the direct predecessor to the C programming language)
- Who is Ken Thompson
- How does a shell work
- What is a pid and a ppid
- How to manipulate the environment of the current process
- What is the difference between a function and a system call
- How to create processes
- What are the three prototypes of main
- How does the shell use the PATH to find the programs
- How to execute another program with the execve system call
- How to suspend the execution of a process until one of its children terminates
- What is EOF / “end-of-file”?
Task 0: Write a README Write a man for your shell. You should have an AUTHORS file at the root of your repository, listing all individuals having contributed content to the repository. Format,
Task 1: Write a beautiful code that passes the Betty checks
Task 2: Write a UNIX command line interpreter.
Usage: simple_shell Your Shell should:
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. The command lines are simple, no semicolons, no pipes, no redirections or any other advanced features. The command lines are made only of one word. No arguments will be passed to programs. If an executable cannot be found, print an error message and display the prompt again. Handle errors. You have to handle the “end of file” condition (Ctrl+D) You don’t have to:
use the PATH implement built-ins handle special characters : ", ', `, , *, &, # be able to move the cursor handle commands with arguments
Task 3: Handle command lines with arguments
Task 4: Simple shell 0.2 +
Handle the PATH fork must not be called if the command doesn’t exist
Task 5: Simple shell 0.3 +
Implement the exit built-in, that exits the shell Usage: exit You don’t have to handle any argument to the built-in exit
Task 6: Simple shell 0.4 +
Implement the env built-in, that prints the current environment
Task 7: Write a blog post describing step by step what happens when you type ls -l *.c and hit Enter in a shell. Try to explain every step you know of, going in as much details as you can, give examples and draw diagrams when needed. You should merge your previous knowledge of the shell with the specifics of how it works under the hoods (including syscalls).
Have at least one picture, at the top of the blog post Publish your blog post on Medium or LinkedIn Share your blog post at least on LinkedIn Only one blog post by team The blog post must be done and published before the first deadline (it will be part of the manual review) Please, remember that these blogs must be written in English to further your technical ability in a variety of settings When done, please add all urls below (blog post, LinkedIn post, etc.) Medium blog post
the prompt automatically exit when the command does not exit the interactive MODE or (REPL)
The author of this project can be found in the AUTHORS file of this project.
- can work in interactive mode
- can also work in non-interactive mode