Cu 2

.container-use/AGENT.md

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+No instructions found. Please look around the filesystem and update me

.container-use/environment.json

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+{
+  "workdir": "/workdir",
+  "base_image": "ubuntu:24.04"
+}

CLAUDE.md

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+ALWAYS use ONLY Environments for ANY and ALL file, code, or shell operations—NO EXCEPTIONS—even for simple or generic requests.
+
+DO NOT install or use the git cli with the environment_run_cmd tool. All environment tools will handle git operations for you. Changing ".git" yourself will compromise the integrity of your environment.
+
+You MUST inform the user how to view your work using `cu log <env_id>` AND `cu checkout <env_id>`. Failure to do this will make your work inaccessible to others.

LICENSE

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+MIT License
+
+Copyright (c) 2025
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

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-# code-challenges
+# Code Challenges
+
+This repository contains a collection of coding challenges and implementations, covering various programming concepts, tools, and system designs.
+
+## Projects
+
+### System Tools & Utilities
+- **cat** - File concatenation utility
+- **cut** - Text column extraction tool
+- **grep** - Pattern searching utility
+- **head** - File header display tool
+- **sed** - Stream editor implementation
+- **tar** - Archive manipulation tool
+- **uniq** - Duplicate line removal utility
+- **wc** - Word, line, and character counting tool
+
+### Network & System Services
+- **forward-proxy** - HTTP proxy server implementation
+- **memcache-server** - In-memory caching server
+- **monitoring-service** - URL monitoring and alerting system
+- **port-scanner** - Network port scanning utility
+- **rate-limiter** - Request rate limiting service
+- **redis-cli** - Redis client implementation
+
+### Development Tools
+- **file-finder** - File search and discovery tool
+- **git-contribution** - Git contribution graph generator
+- **shell** - Command shell implementation
+- **static-site-generator** - Static website generator
+- **zipcracker** - ZIP file password cracking utility
+
+### Specialized Applications
+- **cron-decoder** - Cron expression parser and decoder
+- **password-manager** - Secure password management system
+
+## Languages & Technologies
+
+Projects in this repository are implemented using various programming languages including:
+- Go
+- Python
+- JavaScript/Node.js
+- Shell scripting
+
+## Getting Started
+
+Each project directory contains its own implementation with relevant source files, dependencies, and documentation. Navigate to individual project directories to explore specific implementations.
+
+## Structure
+
+```
+├── project-name/
+│   ├── source files
+│   ├── dependencies (go.mod, package.json, etc.)
+│   └── project-specific files
+└── README.md
+```
+
+## Contributing
+
+This repository serves as a collection of coding challenges and learning exercises. Each project demonstrates different programming concepts, algorithms, and system design patterns.

top/go.mod

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+module top
+
+go 1.24.0
+
+require golang.org/x/term v0.34.0
+
+require golang.org/x/sys v0.35.0 // indirect

top/go.sum

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+golang.org/x/sys v0.35.0 h1:vz1N37gP5bs89s7He8XuIYXpyY0+QlsKmzipCbUtyxI=
+golang.org/x/sys v0.35.0/go.mod h1:BJP2sWEmIv4KK5OTEluFJCKSidICx8ciO85XgH3Ak8k=
+golang.org/x/term v0.34.0 h1:O/2T7POpk0ZZ7MAzMeWFSg6S5IpWd/RXDlM9hgM3DR4=
+golang.org/x/term v0.34.0/go.mod h1:5jC53AEywhIVebHgPVeg0mj8OD3VO9OzclacVrqpaAw=

top/main.go

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+package main
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+	"strconv"
+	"strings"
+	"time"
+
+	"golang.org/x/term"
+)
+
+type CPUStats struct {
+	user, nice, system, idle, iowait, irq, softirq, steal uint64
+}
+
+var prevCPUStats *CPUStats
+
+func main() {
+	// Get the file descriptor for standard input
+	fd := int(os.Stdin.Fd())
+
+	// Check if standard input is a terminal
+	if !term.IsTerminal(fd) {
+		fmt.Println("Not running in a terminal.")
+		return
+	}
+
+	// Save the original terminal state so we can restore it later
+	oldState, err := term.GetState(fd)
+	if err != nil {
+		panic(err)
+	}
+	defer term.Restore(fd, oldState)
+
+	// Put the terminal into raw mode. This disables input echoing.
+	_, err = term.MakeRaw(fd)
+	if err != nil {
+		panic(err)
+	}
+
+	// Take two quick readings to calculate initial CPU usage
+	prevCPUStats, _ = readCPUStats()
+	time.Sleep(100 * time.Millisecond) // Very brief pause
+	printSystemInfo()
+
+	// Create a ticker for 5-second intervals
+	ticker := time.NewTicker(5 * time.Second)
+	defer ticker.Stop()
+
+	// Channel for keyboard input
+	inputCh := make(chan byte, 1)
+
+	// Goroutine to handle keyboard input
+	go func() {
+		for {
+			var buf [1]byte
+			_, err := os.Stdin.Read(buf[:])
+			if err != nil {
+				return
+			}
+			inputCh <- buf[0]
+		}
+	}()
+
+	// Main event loop
+	for {
+		select {
+		case <-ticker.C:
+			printSystemInfo()
+
+		case char := <-inputCh:
+			// Handle keyboard input
+			if char == 'q' || char == 'Q' || char == 3 { // 'q', 'Q', or Ctrl+C
+				fmt.Println()
+				return
+			}
+		}
+	}
+}
+
+func readCPUStats() (*CPUStats, error) {
+	file, err := os.Open("/proc/stat")
+	if err != nil {
+		return nil, err
+	}
+	defer file.Close()
+
+	scanner := bufio.NewScanner(file)
+	if !scanner.Scan() {
+		return nil, fmt.Errorf("failed to read CPU line")
+	}
+
+	line := scanner.Text()
+	fields := strings.Fields(line)
+	if len(fields) < 8 || fields[0] != "cpu" {
+		return nil, fmt.Errorf("invalid CPU line format")
+	}
+
+	stats := &CPUStats{}
+	values := []*uint64{&stats.user, &stats.nice, &stats.system, &stats.idle,
+		&stats.iowait, &stats.irq, &stats.softirq, &stats.steal}
+
+	for i, val := range values {
+		parsed, err := strconv.ParseUint(fields[i+1], 10, 64)
+		if err != nil {
+			return nil, err
+		}
+		*val = parsed
+	}
+
+	return stats, nil
+}
+
+func calculateCPUUsage(prev, curr *CPUStats) float64 {
+	if prev == nil {
+		return 0.0
+	}
+
+	prevTotal := prev.user + prev.nice + prev.system + prev.idle + prev.iowait + prev.irq + prev.softirq + prev.steal
+	currTotal := curr.user + curr.nice + curr.system + curr.idle + curr.iowait + curr.irq + curr.softirq + curr.steal
+
+	totalDiff := currTotal - prevTotal
+	idleDiff := curr.idle - prev.idle
+
+	if totalDiff == 0 {
+		return 0.0
+	}
+
+	return (1.0 - float64(idleDiff)/float64(totalDiff)) * 100.0
+}
+
+func printSystemInfo() {
+	currentTime := time.Now()
+	cpuStats, err := readCPUStats()
+
+	var cpuUsage float64
+	if err == nil {
+		cpuUsage = calculateCPUUsage(prevCPUStats, cpuStats)
+		prevCPUStats = cpuStats
+	}
+
+	if err != nil {
+		fmt.Printf("\rTime: %s | CPU: --%%", currentTime.Format("15:04:05"))
+	} else {
+		fmt.Printf("\rTime: %s | CPU: %.1f%%", currentTime.Format("15:04:05"), cpuUsage)
+	}
+}