0x16. C - Simple Shell

SIMPLE SHELL

• We created a basic version of the Unix shell from scratch. A program that takes commands from the keyboard and gives them to the operating system to perform. The shell can perform commands such as listing files in current working directory by typing ls, exit, among others. It works in both interactive and non-interactive mode.

• The following are the allowed functions and system calls;

  • access, chdir, close, closedir, execve, exit, _exit, fflush, fork,free, getcwd, getline, getpid, isatty, kill, malloc, open, opendir, perror, read, readdir, signal, stat, lstat, fstat, strtok, wait, waitpid, wait3, wait4, write.

• This simple shell is a Shell interface written in C programming language that gives to the user a prompt #cisfun$ , after it accepts, it executes a user inputted command in a separate process called child process.

File Descriptions

• AUTHORS: Has the names of this project's contributors.
• _execute.c: Contains the function that executes shell commands.
• _strings1.c, _strings2.c, _strings3.c: Contains functions that are used to manipultate and get data about strings like finding string length and splitting a string.
• built-in.c: Includes functions to perform built-in shell command operations like exit.
• main.h: Holds all function prototypes and headers.
• main.c: The shell's entry point i.e contains the main method.
• man_1_simple_shell: A manual for the shell.
• prompt.c: Prints the shell's title to indicate the shell is ready to receive input.
• readline: Responsible for picking commands typed into the shell.
• handle_path.c: Contains functions used to handle cases when a command is entered into the shell instead of the path to the executable file. For example when a user types ls instead of \bin\ls;

Builtin functions

List of builtin funtion supported by this simple shell:

Buitin Function	Descriptions
env	Print current environment variables
setenv	Set new environment variable setenv var_name va_value
unsetenv	Remove environment variable unsetenv var_name va_value

How to use the shell:

• Install;

(your_terminal)$ git clone <this repository>
(your_terminal)$ cd simple_shell

• Compile:

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

• Usage: non-interactive mode

echo "/bin/ls" | ./hsh

• Usage: interactive mode

(your_terminal)$ ./hsh

Example

#cisfun$ /bin/ls -l
total 100
-rw-r--r-- 1 runner runner  2029 May 24 05:49 _env.c
-rw-r--r-- 1 runner runner  1052 May 19 13:26 _execute.c
-rw-r--r-- 1 runner runner  1767 May 19 13:27 _strings1.c
-rw-r--r-- 1 runner runner  1351 May 24 05:53 _strings2.c
-rw-r--r-- 1 runner runner  2516 May 19 13:29 _strings3.c
-rw-r--r-- 1 runner runner  2074 May 19 13:30 built-in.c
-rw-r--r-- 1 runner runner  1483 May 19 13:31 handle_path.c
-rwxr-xr-x 1 runner runner 44128 May 24 05:53 main
-rw-r--r-- 1 runner runner   752 May 19 13:21 main.c
-rw-r--r-- 1 runner runner  1225 May 19 13:22 main.h
-rw-r--r-- 1 runner runner  1520 May 24 05:48 man_1_simple_shell
-rw-r--r-- 1 runner runner   164 May 24 05:48 prompt.c
-rw-r--r-- 1 runner runner   506 May 19 13:32 readline.c

#cisfun$ exit
(your_terminal)$

Bugs

At this time, there are no known bugs.

More info on our blog here.

Authors:

1. NIYIBIZI Elysée | Github.
2. MUHAYEMARIYA Faustine | Github.