Custom Shell Implementation

A feature-rich shell implementation in C that provides various Unix-like shell functionalities including process management, I/O redirection, and custom commands.

Features

Basic Shell Operations

• Custom shell prompt showing username, system name, and current directory
• Support for multiple commands using ';' separator
• Background process execution using '&'
• Error handling for invalid commands

Built-in Commands

Directory Navigation

• hop - Change directory with support for:
  • Relative and absolute paths
  • Special symbols (., .., ~, -)
  • Multiple directory arguments
  • Displays full path after changing directory

File Operations

• reveal - List files and directories with:
  • Color coding (green for executables, white for files, blue for directories)
  • Support for -a (show hidden files) and -l (detailed listing) flags
  • Path symbols support (., .., ~, -)

Command History

• log - Command history management:
  • Stores up to 15 most recent commands
  • Persists across sessions
  • log purge - Clear history
  • log execute <index> - Execute command from history

Process Information

• proclore - Display process information:
  • PID
  • Process Status (R/R+/S/S+/Z)
  • Process Group
  • Virtual Memory
  • Executable Path

File Search

• seek - Search for files and directories:
  • -d flag for directories only
  • -f flag for files only
  • -e flag for direct interaction with single match
  • Support for target directory specification

Advanced Features

Process Management

• Background process execution with PID display
• Process completion notification
• Time taken display for foreground processes (>2s)
• activities - List all running processes
• ping - Send signals to processes
• fg/bg - Foreground/Background process control

I/O Redirection and Pipes

• Support for input (<) and output (>, >>) redirection
• Multiple pipe (|) support
• Combined pipes and redirection

Signal Handling

• Ctrl+C (SIGINT) - Interrupt foreground process
• Ctrl+Z - Stop foreground process
• Ctrl+D - Shell exit

Configuration

• .myshrc support for aliases and custom functions
• Customizable shell environment

Networking

• iMan - Fetch man pages from the internet using sockets

Installation

# Clone the repository
git clone <repository-url>

# Navigate to the project directory
# Run the makefile
make

Usage Examples

# Change directory
<username@system:~> hop documents

# List files with details
<username@system:~/documents> reveal -l

# Search for files
<username@system:~> seek -f document ~/

# View command history
<username@system:~> log

# Check process information
<username@system:~> proclore 1234

# Redirect output
<username@system:~> echo "Hello" > output.txt

# Use pipes
<username@system:~> cat file.txt | grep "pattern"

# Fetch man pages
<username@system:~> iMan ls

Error Handling

• Invalid command detection and reporting
• File/directory access permission checks
• Process management error handling
• I/O redirection error handling

Technical Details

• Written in C
• Uses system calls for process management
• Socket programming for network features
• Signal handling implementation
• File descriptor management for I/O operations

Limitations

• Aliases limited to single-word mappings
• Maximum command history of 15 entries

Contributing

Feel free to submit issues and enhancement requests.