Simple Shell

Simple Shell is a simple implementation of the UNIX command interpreter project for ALX school students, where we build and understand how the simple shell command works. The project is to replicate the basic functionality of a LINUX Shell

Learning Objectives

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”?

Requirements

All your files will be compiled on Ubuntu 14.04 LTS.
Your C programs and functions will be compiled with gcc 4.8.4 using the flags -Wall -Werror -Wextra and -pedantic.
All your files should end with a new line.
Your code should use the Betty style.
No more than 5 functions per file.
All your header files should be include guarded.
Use system calls only when you need to.

Contained files

FILE	DESCRIPTION FILE
header.h	contains the prototypes of the functions
PATH.c	contain functions search command in the PATH
simple_shell.c	contain Main functions
str_tok.c	contain function split buffer and aux
_atoi.c	convert string in a number
_cd.c	Function change directory
_execve.c	execute commnads with fork
buffer.c	works in buffer
node.c	creates and deletes node
set_buffer.c	set buffer with NULL
setenv.c	overwrite environment
str_cmp.c	function compare string
str_cpy.c	function copy stryng
str_len.c	function count leng string
str_tok.c	function break strings in tokens
unsetenv.c	function remove variable environment
free.c	free dinamic memory (malloc)
errors.c	Management errors
README.md	README file

Clone Code

simple_shell is clone in your terminal using the next code

git clone: https://github.com/Giddyspurz/simple_shell

How to Copile the code

gcc -Wall -Wextra -Werror -pedantic *.c -o hsh

Run the code

./hsh

Examples to Use

Basics

SHell reads the entry, it proceeds through many sequence of operations and divide it in words and operators.

ls -la

vagrant@vagrant-ubuntu-trusty-64:$ ./hsh
> ls -la
total 128
drwxrwxr-x 4 vagrant vagrant 4096 ago 20 09:59 .
drwxrwxr-x 4 vagrant vagrant 4096 ago 19 20:14 ..
-rw-rw-r-- 1 vagrant vagrant  425 ago 19 17:42 _atoi.c
-rw-rw-r-- 1 vagrant vagrant  158 ago 19 17:42 AUTHORS
-rw-rw-r-- 1 vagrant vagrant 3675 ago 20 09:59 buffer.c
-rw-rw-r-- 1 vagrant vagrant 2718 ago 19 22:01 _cd.c
-rw-rw-r-- 1 vagrant vagrant  498 ago 19 17:42 errors.c
-rw-rw-r-- 1 vagrant vagrant 2409 ago 20 09:59 _execve.c
-rw-rw-r-- 1 vagrant vagrant  342 ago 19 17:42 free.c
-rw-rw-r-- 1 vagrant vagrant  675 ago 19 22:02 function.c
drwxrwxr-x 8 vagrant vagrant 4096 ago 20 10:04 .git
-rw-rw-r-- 1 vagrant vagrant 3994 ago 19 22:01 header.h
drwxrwxr-x 2 vagrant vagrant 4096 ago 19 17:42 imag
-rw-rw-r-- 1 vagrant vagrant 3222 ago 19 17:42 man_1_simple_shell
-rw-rw-r-- 1 vagrant vagrant 2895 ago 19 22:01 node.c
-rw-rw-r-- 1 vagrant vagrant 3375 ago 19 22:01 PATH.c
-rw-rw-r-- 1 vagrant vagrant  588 ago 19 22:02 _print_binary.c
-rw-rw-r-- 1 vagrant vagrant 1168 ago 19 22:03 _printf.c
-rw-rw-r-- 1 vagrant vagrant  607 ago 19 22:03 print_number.c
-rw-rw-r-- 1 vagrant vagrant  575 ago 19 22:03 _print_o.c
-rw-rw-r-- 1 vagrant vagrant  572 ago 19 22:03 _print_u.c
-rw-rw-r-- 1 vagrant vagrant 1236 ago 19 22:03 _print_x.c
-rw-rw-r-- 1 vagrant vagrant 1259 ago 19 22:03 _print_X.c
-rw-rw-r-- 1 vagrant vagrant 3593 ago 20 10:04 README.md
-rw-rw-r-- 1 vagrant vagrant  326 ago 19 17:42 set_buffer.c
-rw-rw-r-- 1 vagrant vagrant 1757 ago 19 22:01 setenv.c
-rw-rw-r-- 1 vagrant vagrant 2552 ago 19 22:01 simple_shell.c
-rw-rw-r-- 1 vagrant vagrant  455 ago 19 17:42 str_cmp.c
-rw-rw-r-- 1 vagrant vagrant  499 ago 19 17:42 str_cpy.c
-rw-rw-r-- 1 vagrant vagrant  225 ago 19 17:42 str_len.c
-rw-rw-r-- 1 vagrant vagrant 2923 ago 19 17:42 str_tok.c
-rw-rw-r-- 1 vagrant vagrant 1890 ago 19 17:42 unsetenv.c
$ pwd
/home/vagrant/simple_shell
$ /bin/pwd
/home/vagrant/simple_shell

Authors

Gad Chege
Jesse Momanyi