A 'simple' Unix shell in C for the School 42 curriculum.
Minishell is a simple Unix shell developed in C as part of the School 42 curriculum. It is a collaborative project developed by Batu and Stefano. The program is being developed with certain constraints: - the strictly adherence to the so called Norm, which imposes certain (at times questionable) limitations such as a maximum function length of 25 lines, the prohibition of for-loops, and more, a restricted set of allowed functions.
- Display a prompt when waiting for a new command.
- Working history.
- Input redirection (
<) and output redirection (>&>>) - Handling of environment variables (like
$PATH) - Signal management for
ctrl-C,ctrl-Dandctrl-\ - Built-in commands support (
echo,cd,pwd,export,unset,exit,pwd) - Quotation handling for both single (
') and double (") quotes - Piping between commands using
| - Expansion for
$?to show exit status of the last executed command - ...
- Clone the repository to your local machine:
git clone https://github.com/552020/minishell.git - Navigate to the relevant directory
cd minishell - Compile the project with
make - Run minishell:
./minishell
Once Minishell is started, you can interact with it like any traditional Unix shell. Enter commands, use redirections (<, >, >>), and pipe commands.
For the development of Minishell, we were restricted to using a specific set of functions. The permitted external functions are:
- I/O Functions:
readline,rl_clear_history,rl_on_new_line,rl_replace_line,rl_redisplay,add_history,printf,write,read,open,close - Memory Management:
malloc,free - Process Management:
fork,wait,waitpid,wait3,wait4,exit,execve - Signal Handling:
signal,sigaction,sigemptyset,sigaddset,kill - File and Directory Handling:
access,getcwd,chdir,stat,lstat,fstat,unlink,dup,dup2,pipe,opendir,readdir,closedir - Error Handling:
strerror,perror - Terminal Control:
isatty,ttyname,ttyslot,ioctl,getenv,tcsetattr,tcgetattr,tgetent,tgetflag,tgetnum,tgetstr,tgoto,tputs
In addition to the aforementioned functions, we were permitted to use our self-coded libft library. This library, a previous project from the School 42 curriculum, contains a set of 40 functions that serve as replacements for common C library functions like strcpy, calloc, and so on.
The most notable restrictions of the norm are:
- the 42 header should be present in every file
- functions must not exceed 25 lines
- global variables are generally not allowed
- the use of ceratin keywords as
for,do...while,switch,case, andgoto. - Comments are not permitted within functions.
- Blank spaces within a function are not allowed, except between variable declarations and the rest of the code.
- All variables must be declared and set at the top of the function.
The entire set of rules and guidelines established by the Norm can be found in the document en.norm.pdf within the repository.