### Install Go on macOS

Source: https://github.com/nao1215/onionscan/blob/main/CONTRIBUTING.md

Installs Go on macOS using Homebrew. Ensure Homebrew is installed first.

```bash
brew install go
```

--------------------------------

### Verify Go Installation

Source: https://github.com/nao1215/onionscan/blob/main/CONTRIBUTING.md

Checks the installed Go version. This command should be run after installing Go.

```bash
go version
```

--------------------------------

### Install OnionScan using Go Install

Source: https://github.com/nao1215/onionscan/blob/main/README.md

Install the latest version of OnionScan directly using the Go toolchain.

```bash
go install github.com/nao1215/onionscan/cmd/onionscan@latest
```

--------------------------------

### Install Go on Ubuntu

Source: https://github.com/nao1215/onionscan/blob/main/CONTRIBUTING.md

Installs Go on Ubuntu using snap or by downloading from the official site. Updates the PATH environment variable.

```bash
# Using snap
sudo snap install go --classic

# Or download from official site
wget https://go.dev/dl/go1.24.0.linux-amd64.tar.gz
sudo tar -C /usr/local -xzf go1.24.0.linux-amd64.tar.gz
echo 'export PATH=$PATH:/usr/local/go/bin' >> ~/.profile
source ~/.profile
```

--------------------------------

### Install Tor on Windows

Source: https://github.com/nao1215/onionscan/blob/main/CONTRIBUTING.md

Installs Tor on Windows using Chocolatey. Ensure Chocolatey is installed first.

```bash
choco install tor
```

--------------------------------

### Verify Development Environment

Source: https://github.com/nao1215/onionscan/blob/main/CONTRIBUTING.md

Runs tests, linter, and builds the project to verify the development environment setup.

```bash
# Run tests
make test

# Run linter
make lint

# Build the project
make build
```

--------------------------------

### Install Tor on macOS

Source: https://github.com/nao1215/onionscan/blob/main/CONTRIBUTING.md

Installs Tor on macOS using Homebrew.

```bash
brew install tor
```

--------------------------------

### Install OnionScan via Homebrew

Source: https://github.com/nao1215/onionscan/blob/main/README.md

Install OnionScan on macOS or Linux using the provided Homebrew tap.

```bash
brew install nao1215/tap/onionscan
```

--------------------------------

### Install Tor on Fedora/RHEL

Source: https://github.com/nao1215/onionscan/blob/main/CONTRIBUTING.md

Installs the Tor package on Fedora or RHEL-based systems.

```bash
sudo dnf install tor
```

--------------------------------

### Install Tor on Arch Linux

Source: https://github.com/nao1215/onionscan/blob/main/CONTRIBUTING.md

Installs the Tor package on Arch Linux.

```bash
sudo pacman -S tor
```

--------------------------------

### OnionScan Configuration File Format

Source: https://github.com/nao1215/onionscan/blob/main/README.md

Example YAML structure for configuring OnionScan, including default settings and site-specific overrides.

```yaml
# Default settings for all sites
defaults:
  cookie: ""
  depth: 100
  headers: {}
  ignore_patterns: []
  follow_patterns: []

# Site-specific configurations
sites:
  exampleonion.onion:
    cookie: "session_id=abc123"
    headers:
      Authorization: "Bearer token"
      X-Custom-Header: "value"
    depth: 50
    ignore_patterns:
      - "/logout"
      - "/admin/*"
    follow_patterns:
      - "/api/*"
      - "/docs/*"

  anotheronion.onion:
    cookie: "auth=xyz789"
    depth: 25
```

--------------------------------

### Install Tor on Ubuntu/Debian

Source: https://github.com/nao1215/onionscan/blob/main/CONTRIBUTING.md

Installs the Tor package on Ubuntu or Debian-based systems.

```bash
sudo apt update && sudo apt install tor
```

--------------------------------

### Go Unit Test Example

Source: https://github.com/nao1215/onionscan/blob/main/CONTRIBUTING.md

Example of a Go unit test using t.Parallel() for parallel execution and t.Run() for subtests. Ensure tests are readable and aim for high coverage.

```go
func TestAnalyzer_Analyze(t *testing.T) {
    t.Parallel()

    t.Run("should detect email addresses", func(t *testing.T) {
        t.Parallel()

        analyzer := NewEmailAnalyzer()
        data := &AnalysisData{
            Pages: []PageData{
                {Content: "Contact: test@example.com"},
            },
        }

        findings, err := analyzer.Analyze(context.Background(), data)
        assert.NoError(t, err)
        assert.Len(t, findings, 1)
    })
}
```

--------------------------------

### OnionScan Text Report Example

Source: https://github.com/nao1215/onionscan/blob/main/README.md

A sample of the default text-based report generated by OnionScan, showing scan metadata, severity summary, detected services, and critical findings.

```text
======================================================================
                         ONIONSCAN REPORT
======================================================================

Hidden Service: exampleonion.onion
Scan Date:      2025-11-30 14:30:00 UTC
Pages Crawled:  42
Status:         Complete

----------------------------------------------------------------------
SEVERITY SUMMARY
----------------------------------------------------------------------

  CRITICAL: 1
  HIGH:     3
  MEDIUM:   5
  LOW:      2
  INFO:     4

  TOTAL:    15 findings

----------------------------------------------------------------------
DETECTED SERVICES
----------------------------------------------------------------------

  - HTTP (80)
  - SSH (22)

----------------------------------------------------------------------
CRITICAL FINDINGS
----------------------------------------------------------------------

  [!] Private Key Exposed
      Type:     Tor v3 Hidden Service Private Key
      Location: /backup/hs_ed25519_secret_key

      The hidden service private key is publicly accessible.
      Anyone can impersonate this hidden service.

...
```

--------------------------------

### Increase Tor Startup Timeout

Source: https://github.com/nao1215/onionscan/blob/main/README.md

If the embedded Tor fails to start, increase the startup timeout using the --tor-timeout flag. This is useful when the Tor process takes longer than the default to initialize.

```bash
onionscan scan --tor-timeout 5m example.onion
```

--------------------------------

### Basic OnionScan

Source: https://github.com/nao1215/onionscan/blob/main/README.md

Scan a single hidden service or multiple services. OnionScan automatically starts an embedded Tor instance if none is running.

```bash
# Scan a hidden service (starts embedded Tor automatically)
onionscan scan exampleonion.onion

# Scan multiple services
onionscan scan site1.onion site2.onion site3.onion
```

--------------------------------

### Initialize OnionScan Configuration

Source: https://github.com/nao1215/onionscan/blob/main/README.md

Creates a default .onionscan configuration file in the current directory.

```bash
onionscan init
```

--------------------------------

### Build OnionScan from Source

Source: https://github.com/nao1215/onionscan/blob/main/README.md

Clone the repository and build the OnionScan executable from the source code.

```bash
git clone https://github.com/nao1215/onionscan.git
cd onionscan
go build -o onionscan ./cmd/onionscan
```

--------------------------------

### Run Tests and Linters

Source: https://github.com/nao1215/onionscan/blob/main/CONTRIBUTING.md

Execute the test suite and run the linter to ensure code quality and adherence to project standards. Verify test coverage meets the minimum requirement.

```bash
# Ensure all tests pass
make test
```

```bash
# Linter check
make lint
```

```bash
# Check coverage (80% or higher)
go test -cover ./...
```

--------------------------------

### OnionScan Politeness Settings

Source: https://github.com/nao1215/onionscan/blob/main/README.md

Configure politeness settings such as crawl delay and user-agent to avoid overwhelming hidden services. Adjust response body size for memory constraints.

```bash
# Slower, more polite scanning (2 second delay)
onionscan scan --crawl-delay 2s exampleonion.onion

# Faster scanning for authorized testing (500ms delay)
onionscan scan --crawl-delay 500ms exampleonion.onion

# Custom User-Agent
onionscan scan --user-agent "MyScanner/1.0" exampleonion.onion

# Limit response body size (useful for memory-constrained environments)
onionscan scan --max-body-size 1048576 exampleonion.onion  # 1MB
```

--------------------------------

### Clone OnionScan Project

Source: https://github.com/nao1215/onionscan/blob/main/CONTRIBUTING.md

Clones the OnionScan repository from GitHub and navigates into the project directory.

```bash
git clone https://github.com/nao1215/onionscan.git
cd onionscan
```

--------------------------------

### OnionScan Output Formats

Source: https://github.com/nao1215/onionscan/blob/main/README.md

Generate scan reports in JSON, Markdown, or plain text formats. Use the -o flag to specify an output file.

```bash
# JSON report
onionscan scan --json -o report.json exampleonion.onion

# Markdown report
onionscan scan --markdown -o report.md exampleonion.onion

# Text report to file
onionscan scan -o report.txt exampleonion.onion
```

--------------------------------

### OnionScan Scan Options

Source: https://github.com/nao1215/onionscan/blob/main/README.md

Customize scan behavior with options like crawl depth, maximum pages, timeout, verbosity, and concurrent scans.

```bash
# Custom crawl depth
onionscan scan --depth 50 exampleonion.onion

# Limit maximum pages to crawl
onionscan scan --max-pages 200 exampleonion.onion

# Custom timeout
onionscan scan --timeout 3m exampleonion.onion

# Verbose logging
onionscan scan -v exampleonion.onion

# Concurrent scans
onionscan scan --batch 5 site1.onion site2.onion site3.onion
```

--------------------------------

### OnionScan Compare Scans

Source: https://github.com/nao1215/onionscan/blob/main/README.md

Compare scan results stored in the local SQLite database to track changes over time. Options include listing history, comparing specific scans, and outputting in JSON or Markdown.

```bash
# Compare latest two scans for a service
onionscan compare exampleonion.onion

# List all scan history for a service
onionscan compare -l exampleonion.onion

# List all scanned services in the database
onionscan compare -L

# Compare with a specific historical scan by ID
onionscan compare -i 5 exampleonion.onion

# Compare scans since a specific date
onionscan compare -s "2025-01-01" exampleonion.onion

# Output comparison in JSON format
onionscan compare -j exampleonion.onion

# Output comparison in Markdown format
onionscan compare -m exampleonion.onion
```

--------------------------------

### Use External Tor Proxy

Source: https://github.com/nao1215/onionscan/blob/main/README.md

When embedded Tor startup fails, configure OnionScan to use an external Tor proxy by specifying its address and port with the -e flag.

```bash
onionscan scan -e 127.0.0.1:9050 example.onion
```

--------------------------------

### OnionScan with External Tor

Source: https://github.com/nao1215/onionscan/blob/main/README.md

Use an existing Tor SOCKS proxy or Tor Browser's proxy for scanning. Specify the host and port of the external Tor service.

```bash
# Use existing Tor SOCKS proxy
onionscan scan --external-tor 127.0.0.1:9050 exampleonion.onion

# Use Tor Browser's proxy
onionscan scan --external-tor 127.0.0.1:9150 exampleonion.onion
```

--------------------------------

### Increase Request Timeout

Source: https://github.com/nao1215/onionscan/blob/main/README.md

To resolve connection timeouts (context deadline exceeded), increase the general request timeout using the --timeout flag. This allows more time for requests to complete, especially for slow or unresponsive hidden services.

```bash
onionscan scan --timeout 5m example.onion
```

--------------------------------

### OnionScan Secure Logging

Source: https://github.com/nao1215/onionscan/blob/main/README.md

OnionScan automatically sanitizes sensitive information like cookies and tokens in log output, even in verbose mode, making logs safe to share for debugging.

```bash
# Verbose mode with automatic secret sanitization
onionscan scan -v exampleonion.onion

# Example output (secrets are masked):
# INFO request sent cookie=***REDACTED*** url=http://example.onion
```

--------------------------------

### Limit Crawl Scope for Large Sites

Source: https://github.com/nao1215/onionscan/blob/main/README.md

To prevent out-of-memory errors on sites with many pages, limit the crawl scope by setting --max-pages and --depth. This restricts the number of pages and the crawl depth to manage resource consumption.

```bash
onionscan scan --max-pages 50 --depth 10 example.onion
```

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