Want to explore some cute shells [ 🐚 ] ? Then, dive into the Occean.

WHAT IS IT, MINISHELL !?

Where There is a SHELL, There is a Way

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• Our first group project during my time at 42, which I collaborated on with @reogine.
• 42 project, recoding our own little bash. A program capable of parsing (which I have done ) a prompt and launching executables with arguments, along with a few built-in functions.
• The objective of this project is to create a simple shell to learn some advanced programming techniques like processes creation and control, file descriptors, signals and pipes, etc.

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WHY?

The existence of shells is linked to the very existence of IT.

At the time, all developers agreed that communicating with a computer using aligned 1/0 switches was seriously irritating.

It was only logical that they came up with the idea of creating a software to communicate with a computer using interactive lines of commands in a language somewhat close to the human language.

Thanks to Minishell, you’ll be able to travel through time and come back to problems people faced when Windows didn’t exist.

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Built-in functions to implement :

Command	Description
echo	Echo the STRING(s) to standart output. -n flag: do not output the trailing newline.
cd	Change the shell working directory (with a relative or absolute path).
pwd	Print name of current/working directory.
export	Set export attribute for shell variables.
unset	Unset values of shell variables.
env	Print the environment.
exit	Cause the shell to exit with the exit status specified.

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Using Only :

Only the following functions are allowed to be used in this project:

Function	Description	Function	Description
readline	read a line from the terminal	lstat	get file status
rl_clear_history	clear the history list by deleting all of the entries	fstat	get file status by fd
rl_on_new_line	tell the update routines that we have moved onto a new line	unlink	remove a specified file
rl_replace_line	replace the contents of rl_line_buffer with text	execve	execute program
rl_redisplay	change what's displayed on the screen	dup	duplicate a file descriptor
add_history	save the line in a history list of lines	dup2	duplicate a file descriptor
printf	format and print data	pipe	create pipe
malloc	allocate dynamic memory	opendir	open a directory
free	free dynamic memory	readdir	read a directory
write	write to a file descriptor	closedir	close a directory
access	check user's permissions for a file	strerror	return string describing error number
open	open and can create a file	perror	print a system error message
read	read from a file descriptor	isatty	test whether a file descriptor refers to a terminal
close	close a file descriptor	ttyname	return name of a terminal
fork	create a child process	ttyslot	find the slot of the current user's terminal in some file
wait	wait for process to change state	ioctl	control device
waitpid	wait for process to change state	getenv	get an environment variable
wait3	wait for process to change state	tcsetattr	control asynchronous communications ports
wait4	wait for process to change state	tcgetattr	control asynchronous communications ports
signal	ANSI C signal handling	tgetent	termcap database emulation
sigaction	examine and change a signal action	tgetflag	termcap database emulation
kill	send signal to a process	tgetnum	termcap database emulation
exit	cause normal process termination	tgetstr	termcap database emulation
getcwd	get current working directory	tgoto	termcap database emulation
chdir	change working directory	tputs	curses interfaces to terminfo database
stat	get file status by pathname

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FOR MORE INFORMATION, CHECK THE SUBJECT : MINISHELL SUBJECT

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About this repo:

1. Clone the repo.
2. Execute make command.
3. Execute ./bin/minishell
4. You will get prompted. then, it's our shell, have fun with it.

Useful ressources :

• https://mywiki.wooledge.org/BashParserhttp://aosabook.org/en/bash.html
• https://www.cs.purdue.edu/homes/grr/SystemsProgrammingBook/Book/Chapter5-WritingYourOwnShell.pdf
• https://tldp.org/LDP/Bash-Beginners-Guide/html/index.html
• https://www.youtube.com/watch?v=cex9XrZCU14&list=PLfqABt5AS4FkW5mOn2Tn9ZZLLDwA3kZUY (Unix processes)
• https://youtu.be/uHH7nHkgZ4w (Pipes)
• https://youtu.be/EqndHT606Tw (fd, dup, dup2)

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the most highlighted learned skill from this project is "How to fix memory leaks, and memory management".

                                               We struggled but we learned :)