The shell is a program that takes commands from the keyboard via the terminal, and gives them to the operating system to perform.
To better understand how the shell actually works, you can read our [Article].
This project is a simple version of the linux shell made for [ALX SOFTWARE ENGINERRING] taking part of the "Simple Shell - Linux and Unix system programming" Project.
It is created using the C programming Language and it can do many functionalities that a real shell does.
Displays a prompt "#cisfun$ " and waits for user input.
Runs all commands of type "executable program" (ls and /bin/ls).
Runs the following build_in commands: exit, env, setenv and unsetenv.
Handles commands with arguments.
Handles the PATH global variable.
Handles The EOF (End Of File) condition.
Handles the Ctrl + C signal -> It doesn't exit the shell
- AUTHORS -> List of contributors to this repository
- man_1_simple_shell -> Manual page for the simple_shell
- shell.h -> Header file
- shell.c -> main function
- sig_handler -> handles the Ctrl + C signal
- _EOF -> handles the End Of File condition
- string.c
- _putchar -> prints a character
- _puts -> prints a string
- _strlen -> gives the length of a string
- _strdup -> copies a string in a newly allocated memory
- concat_all -> concatenates 3 strings in a newly allocated memory
- line_exec.c
- splitstring -> splits a string into an array of words
- execute -> executes a command using execve
- realloc -> reallocates a memory block
- freearv -> frees a 2 dimensional array
- linkpath.c
- _getenv -> returns the value of a global variable
- add_node_end -> adds a node in a singly linked list
- linkpath -> creates a singly linked list for PATH directories
- _which -> finds the pathname of a command
- free_list -> frees the linked list of PATH value
- checkbuild.c
- checkbuild -> checks if a command is a build-in command
- buildin.c
- exitt -> handles the exit buildin command
- _atoi -> converts a string into an integer
- env -> prints the current environment
- _setenv -> Initialize a new global variable, or modify an existing one
- _unsetenv -> remove a global variable
- 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)
- getline (man 3 getline)
- 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)
- strtok (man 3 strtok)
- wait (man 2 wait)
- waitpid (man 2 waitpid)
- wait3 (man 2 wait3)
- wait4 (man 2 wait4)
- write (man 2 write)
You can try our shell by following these steps:
Step 1: Clone our repository using this command, (you need to have git installed on your machine first)
git clone https://github.com/tecnophille/simple_shell
Step 2: Change directory to simple_shell:
cd simple_shell
Step 3: Compile the C files in this way:
gcc -Wall -Werror -Wextra -pedantic *.c -o hsh
Step 4: Run the shell
./hsh
Exiting the shell When you want to exit the shell, you can use one of the following methods:
1: Type the command "exit"
exit
2: Press on Ctrl + D
ubunto@ubuntu:~/OS/simple_shell$ gcc -Wall -Wextra -Werror -pedantic *.c -o hsh
ubunto@ubuntu:~/OS/simple_shell$ ./hsh
#cisfun$ echo Hello, This is an example
Hello, This is an example
#cisfun$ ls
README.md checkbuild.c line_exec.c shell.c string.c
buildin.c hsh linkpath.c shell.h
#cisfun$ ^C
#cisfun$ ls -l
total 52
-rw-r--r-- 1 ubunto ubunto 3067 Aug 9 04:22 README.md
-rw-r--r-- 1 ubunto ubunto 2183 Aug 9 16:17 buildin.c
-rw-r--r-- 1 ubunto ubunto 574 Aug 9 15:59 checkbuild.c
-rwxr-xr-x 1 ubunto ubunto 18144 Aug 9 04:22 hsh
-rw-r--r-- 1 ubunto ubunto 2091 Aug 9 14:49 line_exec.c
-rw-r--r-- 1 ubunto ubunto 199 Aug 9 14:30 linkpath.c
-rw-r--r-- 1 ubunto ubunto 951 Aug 9 16:09 shell.c
-rw-r--r-- 1 ubunto ubunto 1351 Aug 9 15:58 shell.h
-rw-r--r-- 1 ubunto ubunto 1727 Aug 9 14:30 string.c
#cisfun$ exit
ubunto@ubuntu:~/OS/simple_shell$
This project was written as part of the curriculum for ALX Africa. ALX Africa SE course is a full-stack software engineering program that prepares students for careers in the tech industry using project-based peer learning. For more information, visit (https://www.alxafrica.com/).