Custom Shell Project

Overview

This project is a custom-built shell written entirely in C. It mimics the behavior of a Unix terminal, supporting basic built-in commands (cd, exit, etc.), piping (|), input/output redirection (<, >), and background execution (&). It was built to deepen my understanding of process creation, forking, and inter-process communication in operating systems.

Features

• Command parsing and tokenization
• Execution of built-in and external commands
• Support for I/O redirection (<, >)
• Support for pipelines (|)
• Background execution (&)

Demo

Here's a quick demo of the shell in action:

Sample Code

void parse_command(char *command, struct pish_arg *arg)
{
    // TODO
    // 1. Clear out the arg struct
    // 2. Parse the `command` buffer and update arg->argc & arg->argv.
    arg->argc = 0;
    char *token = strtok(command, " \t\n");
    while (token != NULL && arg->argc < MAX_ARGC - 1) {
        arg->argv[arg->argc++] = token;
        token = strtok(NULL, " \t\n");
    }	
                
    arg->argv[arg->argc] = NULL;
}
            

Explore the Code

Check out the full project on GitHub, or download it directly.

What I Learned

This project strengthened my understanding of how Unix systems manage processes. I learned how to fork child processes, manipulate file descriptors for I/O redirection, and implement a command parser from scratch.