ZASH - Homemade Linux Shell

Overview

ZASH is a minimal Unix-like shell implemented in C for Linux systems. This project was created as part of an operating systems class at Cooper Union in October 2025 (ECE-357). It demonstrates fundamental system calls and process management concepts through a functional command-line interface.

Features

• Command Parsing: Tokenizes and executes user commands with proper argument handling
• I/O Redirection: Supports input redirection (<), output redirection (>, >>), and error redirection (2>, 2>>)
• Built-in Commands: Implements cd, pwd, and exit with appropriate functionality
• Process Management: Uses fork/exec/wait to execute external commands
• Resource Tracking: Displays real, user, and system time for each command execution
• Scripting Support: Can read commands from files or standard input
• Error Handling: Comprehensive error reporting for file operations and command execution

System Calls Demonstrated

• fork() - Process creation
• execvp() - Program execution
• wait3() - Process synchronization with resource usage
• dup2() - File descriptor manipulation for redirection
• open() - File operations
• chdir() - Directory changes
• getcwd() - Current working directory retrieval
• gettimeofday() - Timing measurements
• getrusage() - Resource usage statistics

Building and Running

Prerequisites

• Linux operating system
• GCC compiler
• Standard C libraries