diff --git a/projects/02-command-line-mastery/play.sh b/projects/02-command-line-mastery/play.sh
index 7167a80..5e1ca2a 100644
--- a/projects/02-command-line-mastery/play.sh
+++ b/projects/02-command-line-mastery/play.sh
@@ -8,44 +8,183 @@ CHALLENGE_DIR=~/challenge
 GREEN='\033[0;32m'
 YELLOW='\033[1;33m'
 BLUE='\033[0;34m'
+RED='\033[0;31m'
 NC='\033[0m'
 
+# Error handling
+set -o errexit  # Exit on error
+set -o nounset  # Exit on undefined variable
+set -o pipefail # Exit on pipe failure
+
+# Trap errors and provide error message
+trap 'echo -e "${RED}Error: Command failed at line $LINENO${NC}" >&2' ERR
+
+# Function to check if command exists
+check_command() {
+    if ! command -v "$1" &>/dev/null; then
+        echo -e "${RED}Error: Required command '$1' not found${NC}"
+        return 1
+    fi
+}
+
+# Function to check required commands
+check_requirements() {
+    local required_commands=("find" "grep" "awk" "sed" "mkdir" "chmod" "touch")
+    local missing_commands=()
+
+    for cmd in "${required_commands[@]}"; do
+        if ! check_command "$cmd"; then
+            missing_commands+=("$cmd")
+        fi
+    done
+
+    if [[ ${#missing_commands[@]} -gt 0 ]]; then
+        echo -e "${RED}Error: Missing required commands: ${missing_commands[*]}${NC}"
+        return 1
+    fi
+}
+
+# Function to clean up previous environment
+cleanup_environment() {
+    echo -e "${BLUE}Cleaning up previous environment...${NC}"
+    if [[ -d "$CHALLENGE_DIR" ]]; then
+        if ! rm -rf "$CHALLENGE_DIR" 2>/dev/null; then
+            echo -e "${RED}Error: Failed to remove directory: $CHALLENGE_DIR${NC}"
+            echo -e "${YELLOW}Tip: Check if you have proper permissions${NC}"
+            return 1
+        fi
+        echo -e "${GREEN}Previous environment cleaned up${NC}"
+    fi
+}
+
 # Function to setup the environment
 setup_environment() {
     echo -e "${BLUE}Setting up challenge environment...${NC}"
     
-    # Create directory structure
-    mkdir -p "$CHALLENGE_DIR"/{files,backup,temp}
-    mkdir -p "$CHALLENGE_DIR/.tracking/data"
+    # Check requirements first
+    if ! check_requirements; then
+        echo -e "${RED}Error: Setup failed - missing requirements${NC}"
+        return 1
+    }
     
-    # Copy all setup scripts to tracking directory
-    cp "$PROJECT_DIR"/setup/*.sh "$CHALLENGE_DIR/.tracking/"
-    chmod +x "$CHALLENGE_DIR/.tracking/"*.sh
+    # Clean up first
+    cleanup_environment
     
-    # Initialize tracking files
+    # Create directory structure with error checking
+    local dirs=(
+        "$CHALLENGE_DIR"/{files,backup,temp}
+        "$CHALLENGE_DIR/.tracking/data"
+    )
+    
+    for dir in "${dirs[@]}"; do
+        if ! mkdir -p "$dir"; then
+            echo -e "${RED}Error: Failed to create directory: $dir${NC}"
+            return 1
+        fi
+    done
+    
+    # Create project directories with error checking
+    for i in {1..5}; do
+        local project_dirs=(
+            "$CHALLENGE_DIR/files/project$i"/{src,config,logs,data}
+        )
+        for dir in "${project_dirs[@]}"; do
+            if ! mkdir -p "$dir"; then
+                echo -e "${RED}Error: Failed to create project directory: $dir${NC}"
+                return 1
+            fi
+        done
+    done
+    
+    # Copy setup scripts with error checking
+    if ! cp "$PROJECT_DIR"/setup/*.sh "$CHALLENGE_DIR/.tracking/" 2>/dev/null; then
+        echo -e "${RED}Error: Failed to copy setup scripts${NC}"
+        echo -e "${YELLOW}Tip: Check if setup scripts exist in: $PROJECT_DIR/setup/${NC}"
+        return 1
+    fi
+    
+    # Set permissions with error checking
+    if ! chmod +x "$CHALLENGE_DIR/.tracking/"*.sh 2>/dev/null; then
+        echo -e "${RED}Error: Failed to set script permissions${NC}"
+        return 1
+    fi
+    
+    # Initialize tracking files with error checking
     local data_dir="$CHALLENGE_DIR/.tracking/data"
-    touch "$data_dir"/{progress,score,challenge,commands,time,hints_used,achievements,attempts}.csv
+    local tracking_files=(progress score challenge commands time hints_used achievements attempts)
+    
+    for file in "${tracking_files[@]}"; do
+        if ! touch "$data_dir/$file.csv" 2>/dev/null; then
+            echo -e "${RED}Error: Failed to create tracking file: $file.csv${NC}"
+            return 1
+        fi
+    done
     
     echo -e "${GREEN}Environment setup complete!${NC}"
 }
 
+# Function to validate challenge ID
+validate_challenge_id() {
+    local id=$1
+    if [[ ! $id =~ ^[1-9]\.[1-5]$ ]]; then
+        echo -e "${RED}Error: Invalid challenge ID format${NC}"
+        echo -e "${YELLOW}Tip: Challenge ID should be in format 'level.number' (e.g., 1.1)${NC}"
+        return 1
+    fi
+}
+
 # Function to start a challenge
 start_challenge() {
     local challenge_id=$1
     
-    # Source required scripts
-    source "$CHALLENGE_DIR/.tracking/common.sh"
-    source "$CHALLENGE_DIR/.tracking/challenges.sh"
+    # Validate challenge ID
+    if ! validate_challenge_id "$challenge_id"; then
+        return 1
+    fi
+    
+    # Source required scripts with error checking
+    local required_scripts=(common.sh challenges.sh)
+    for script in "${required_scripts[@]}"; do
+        if ! source "$CHALLENGE_DIR/.tracking/$script" 2>/dev/null; then
+            echo -e "${RED}Error: Required script not found: $script${NC}"
+            echo -e "${YELLOW}Running setup first...${NC}"
+            setup_environment
+            if ! source "$CHALLENGE_DIR/.tracking/$script" 2>/dev/null; then
+                echo -e "${RED}Error: Failed to source $script even after setup${NC}"
+                return 1
+            fi
+        fi
+    done
     
     clear
     echo -e "${GREEN}🎮 Command Line Mastery Challenge${NC}"
     echo "=============================="
     
-    get_challenge_details "$challenge_id"
-    bash "$CHALLENGE_DIR/.tracking/level1-setup.sh"
+    # Setup challenge environment with error checking
+    if ! get_challenge_details "$challenge_id" 2>/dev/null; then
+        echo -e "${RED}Error: Challenge $challenge_id not found${NC}"
+        echo -e "${YELLOW}Available challenges:${NC}"
+        list_challenges
+        return 1
+    fi
     
+    if ! bash "$CHALLENGE_DIR/.tracking/level1-setup.sh" 2>/dev/null; then
+        echo -e "${RED}Error: Failed to setup challenge environment${NC}"
+        echo -e "${YELLOW}Try running: $0 clean && $0 setup${NC}"
+        return 1
+    fi
+    
+    # Record challenge start with error checking
     local start_time=$(date +%s)
-    echo "$challenge_id,$start_time" > "$CHALLENGE_DIR/.tracking/current_challenge"
+    if ! echo "$challenge_id,$start_time" > "$CHALLENGE_DIR/.tracking/current_challenge" 2>/dev/null; then
+        echo -e "${RED}Error: Failed to record challenge start${NC}"
+        return 1
+    fi
+    
+    # Create command aliases
+    alias verify="$CHALLENGE_DIR/.tracking/verify-challenge.sh"
+    alias hint="$CHALLENGE_DIR/.tracking/show-hint.sh"
+    alias status="$CHALLENGE_DIR/.tracking/track-progress.sh"
     
     echo -e "\n${GREEN}Challenge ready!${NC}"
     echo -e "Commands available:"
@@ -63,46 +202,57 @@ Commands:
     start <challenge-id>  Start a specific challenge
     list                 List available challenges
     setup                Setup/reset the environment
+    clean                Remove all challenge files
     help                 Show this help message
 
 Examples:
     $0 setup            # First time setup
+    $0 clean            # Remove all challenge files
     $0 list             # Show available challenges
     $0 start 1.1        # Start challenge 1.1
 EOF
 }
 
-# Main execution
-case "$1" in
-    "setup")
-        setup_environment
-        ;;
-    "start")
-        if [[ ! -d "$CHALLENGE_DIR/.tracking" ]]; then
-            echo -e "${YELLOW}Environment not set up. Running setup first...${NC}"
+# Main execution with error handling
+main() {
+    case "$1" in
+        "setup")
             setup_environment
-        fi
-        if [[ -z "$2" ]]; then
-            echo "Error: Please specify a challenge ID"
-            echo "Example: $0 start 1.1"
-            exit 1
-        fi
-        start_challenge "$2"
-        ;;
-    "list")
-        if [[ -f "$CHALLENGE_DIR/.tracking/challenges.sh" ]]; then
-            source "$CHALLENGE_DIR/.tracking/challenges.sh"
+            ;;
+        "clean")
+            cleanup_environment
+            ;;
+        "start")
+            if [[ -z "${2:-}" ]]; then
+                echo -e "${RED}Error: Please specify a challenge ID${NC}"
+                echo "Example: $0 start 1.1"
+                return 1
+            fi
+            start_challenge "$2"
+            ;;
+        "list")
+            if [[ ! -f "$CHALLENGE_DIR/.tracking/challenges.sh" ]]; then
+                setup_environment
+            fi
+            if ! source "$CHALLENGE_DIR/.tracking/challenges.sh" 2>/dev/null; then
+                echo -e "${RED}Error: Failed to load challenges${NC}"
+                return 1
+            fi
             list_challenges
-        else
-            echo "Please run setup first: $0 setup"
-        fi
-        ;;
-    "help"|"--help"|"-h"|"")
-        show_help
-        ;;
-    *)
-        echo "Unknown command: $1"
-        show_help
-        exit 1
-        ;;
-esac 
\ No newline at end of file
+            ;;
+        "help"|"--help"|"-h"|"")
+            show_help
+            ;;
+        *)
+            echo -e "${RED}Unknown command: $1${NC}"
+            show_help
+            return 1
+            ;;
+    esac
+}
+
+# Run main with error handling
+if ! main "${@:-}"; then
+    echo -e "${RED}Command failed. See errors above.${NC}"
+    exit 1
+fi 
\ No newline at end of file