Mini Shell

A simplified Unix-like shell implemented in C.
It supports executing built-in and external commands, handling environment variables, and managing input/output redirection, pipes, and sequential execution.

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Overview

This project replicates the core functionality of a command-line interpreter.
It parses commands, executes them via system calls (fork, execvp, dup2, waitpid), and manages redirections and environment variables dynamically.

Language: C
Focus: System calls, process management, I/O redirection, shell parsing

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Features

Built-in Commands

• cd — change the current working directory (cd, cd .., cd -, cd ~)
• exit / quit — close the shell and free resources

Environment Variables

• Supports assignments (VAR=value) and variable expansion ($VAR)
• Allows dynamic updates using setenv and getenv

Command Execution

• Runs external programs via execvp
• Supports conditional execution (&&, ||), sequencing (;), and piping (|)
• Implements input (<), output (>), append (>>), and error redirection (2>, 2>>)

Architecture

• cmd.c — core command execution (built-ins, redirections, pipes, conditions)
• utils.c — string parsing and argument handling for execvp
• main.c — user input loop, command parsing, and interactive shell interface

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Example Session

VAR=hello
echo $VAR
hello
cd ..
ls -l | grep ".c"
exit

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Learning Outcomes

• Implemented process creation, synchronization, and inter-process communication.
• Practiced redirection, piping, and file descriptor manipulation.
• Deepened understanding of command parsing and execution in Unix systems.