Shell

Last Holbertonschool C programming language roject.

Description

0x16. C Write a simple UNIX command interpreter. The shell is the command interpretor in an operating system such as Unix or GNU/Linux. It provides a computer user an interface to the Unix/GNU Linux system so that the user can run different commands or utilities/tools with some input data.

Functionality

1. Clone this repository

$ git clone https://github.com/mrdoomus/simple_shell.git

2. Change directory to "simple_shell"

$ cd simple_shell

3. Make use of the Makefile file by typing "make". This will compile and execute the shell.

$ make

If you're having problems with the Makefile, just copy and paste the following command, it will compile and execute the shell.

$ gcc shell.c -Wall -Werror -Wextra -pedantic _* -o shell && ./shell

Examples

First of all, the shell has two possible forms:

INTERACTIVE

Where the shell stays on a loop prompting the user's input, then executes it, after executing the output is shown and finally the shell goes back to prompting.

$ pwd
/home/vagrant/simple_shell
$

NON INTERACTIVE

Where the shell doesn't loop, it just executes the written command on echo and closing when finished.

$ echo "pwd" | ./shell
/home/vagrant/simple_shell

---

EXAMPLES (Interactive mode)

• Flags to commands

$ ls -la
drwxrwxr-x 3 vagrant vagrant  4096 Aug 27 03:09 .
drwxr-xr-x 8 vagrant vagrant  4096 Aug 27 03:09 ..
-rw-rw-r-- 1 vagrant vagrant   197 Aug 27 02:40 AUTHORS
-rw-rw-r-- 1 vagrant vagrant  1197 Aug 27 02:40 _builtins.c
-rw-rw-r-- 1 vagrant vagrant   832 Aug 27 02:40 _execute.c
-rw-rw-r-- 1 vagrant vagrant   367 Aug 27 02:40 _freegrid.c
-rw-rw-r-- 1 vagrant vagrant   319 Aug 27 02:40 _getline.c
drwxrwxr-x 8 vagrant vagrant  4096 Aug 27 02:40 .git
-rw-rw-r-- 1 vagrant vagrant   203 Aug 27 02:40 Makefile
-rw-rw-r-- 1 vagrant vagrant  1458 Aug 27 02:40 _pathfinder.c
-rw-rw-r-- 1 vagrant vagrant  1168 Aug 27 02:40 pathfinderSave.c
-rw-rw-r-- 1 vagrant vagrant  1593 Aug 27 03:09 README.md
-rwxrwxr-x 1 vagrant vagrant 23547 Aug 27 03:05 shell
-rw-rw-r-- 1 vagrant vagrant  2011 Aug 27 02:40 shell.c
-rw-rw-r-- 1 vagrant vagrant   736 Aug 27 02:40 shell.h
-rw-rw-r-- 1 vagrant vagrant   611 Aug 27 02:40 _splitline.c
-rw-rw-r-- 1 vagrant vagrant   334 Aug 27 02:40 _strcat.c
-rw-rw-r-- 1 vagrant vagrant   417 Aug 27 02:40 _strcmp.c
-rw-rw-r-- 1 vagrant vagrant   406 Aug 27 02:40 _strcpy.c
-rw-rw-r-- 1 vagrant vagrant   226 Aug 27 02:40 _strlen.c
-rw-rw-r-- 1 vagrant vagrant   514 Aug 27 02:40 _strstr.c
$

• Changing directory

$ cd -
/home/vagrant/
$ cd simple_shell
$ pwd
/home/vagrant/simple_shell
$

• Creating and deleting files

$ touch file1
$ ls
AUTHORS      _freegrid.c    pathfinderSave.c  shell.h       _strcpy.c
_builtins.c  _getline.c     README.md         _splitline.c  _strlen.c
_execute.c   Makefile       shell             _strcat.c     _strstr.c
file1        _pathfinder.c  shell.c           _strcmp.c
$ rm file1
$ ls
AUTHORS      _freegrid.c  _pathfinder.c     shell    _splitline.c  _strcpy.c
_builtins.c  _getline.c   pathfinderSave.c  shell.c  _strcat.c     _strlen.c
_execute.c   Makefile     README.md         shell.h  _strcmp.c     _strstr.c
$

Files

This is a table with the files and their respective description used to create the shell.

File	Description
shell.c	Main function, selects if interactive or non interactive, also calls the other functions
shell.h	Header file, contains prototypes of every function used
_getline.c	Gets the user's input and returns the typed command
_splitline.c	Splits the command into arguments for processing
_pathfinder.c	Finds path of execution for first argument (command) if ir wasn't typed fully
_execute.c	Executes the the command and returns a status for continuing or stopping the main loop
_builtins.c	Special commands innate of thell, no need of pathfinding
_strcat.c	Concatenates one string into another _strcat(hello, world => helloworld)
_strcmp.c	Compares two strings and returns 0 if equals _strcmp(hello, hello => 0)
_strcpy.c	Copy one string into an empty pointer _strcpy(newName(empty), name(Camilo) => newName(Camilo))
_strlen.c	Returns the number of chars (without null) of a string _strlen(name(Camilo) => 5)
Makefile	Compiles and executes the shell

Version

• 0.1 (28 | 08 | 2019) First version

Authors

Juan Alberto Londoño Hernández [email protected] (Juan pequeño)

Camilo José Villegas Jiménez [email protected] (DOOM)

Acknowledgments

ALL THE HOLBERTON ALUMNI, THANKS! <3