C PROGRAMMING – Simple Shell Project

Description

What you should learn from this project:

• Who designed and implemented the original Unix operating system? Dennis Ritchie, Doug McIlroy, and Peter G. Neumann also credit Kernighan.
• Who wrote the first version of the UNIX shell? Ken Thompson
• Who invented the B programming language? Ken Thompson & Dennis Ritchie
• Who is Ken Thompson? An original developer of the Unix Shell
• How does a shell work?
• What is a pid and a ppid?
• Learn how to manipulate the environment of the current process.
• What is the difference between a function and a system call?
• Learn how to create processes.
• How does the shell use the PATH to find the programs?
• Learn how to execute another program with the execve system call.
• Learn how to suspend the execution of a process until one of its children terminates.
• What is EOF / “end-of-file”?

• What are the three prototypes of main?
• int main(void)
• int main(int ac, char **av)
• int main(int ac, char **av, char **env)

0. README

• A README file that describes the simple shell project

0. man page

• This file contains the functions utilized in our Shell program

0. AUTHORS Acknowledgement

• This file details contacts of the authors of this shell project

1. Betty would be proud

• A beautiful code that passes the betty checks.

2. Simple shell 0.1

• Write a UNIX command line interpreter.

• What should your shell do?
• 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)
• Test the file in C

3. Simple shell 0.2

• Our 0.1+ shell can handle command lines with arguments

4. Simple shell 0.3

• Our 0.2+ simple shell can handle the PATH

5. Simple shell 0.4

• Implement the exit built in that exits the shell 0.3+

6. Simple shell 1.0

• Implement the shell build in, that prints the current environment

Task 7. What happens when you type ls -l in the shell?

• Write a blog post describing step by step what happens

• Blog post should contain the following
• 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 Twitter and LinkedIn
• Only one blog post by team
• The blog post must be done and published before the first deadline
• Please, remember that these blogs must be written in English to further your technical ability in a variety of settings
• Remember to add the URLs for blog post and tweet

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Resources

1. https://cvw.cac.cornell.edu/Linux/howwork
2. https://stackoverflow.com/questions/30493424/what-is-the-difference-between-a-process-pid-ppid-uid-euid-gid-and-egid
3. https://www.quora.com/What-is-the-difference-between-a-function-call-and-a-system-call-in-an-operating-system

4. Shout outs!

   1. [Drew](https://github.com/dmaring) - Effective usage of builtin GDB
   2. [Ben](https://github.com/VieetBubbles) - Understanding Parent & child
   3. [Farrukh](https://github.com/narnat) - Working with arrays
   4. [Tim](https://github.com/tassavarat) - Debugging accomodating newline
   5. [Arthur](https://github.com/arthurdamm) - Debugging our PWD error

   Authors

   • Koome Mwiti - komerela

   • LinkedIn - koomemwiti

   • Julienne Tesoro - jmtes

   • LinkedIn - juliennetesoro