Subdomains play a crucial role in the structure and navigation of websites. They can be indicative of different services, regions, or purposes under the umbrella of the main domain. However, from a cybersecurity perspective, each subdomain can also be a potential entry point for attackers. As applications grow in complexity, managing and keeping track of subdomains becomes increasingly challenging.

The Subdomains CLI Tool is designed to simplify this process. By leveraging the power of the subdomain.center API, it provides a streamlined method to fetch and list subdomains associated with a primary domain. This is not only beneficial for developers and website administrators in managing their online assets but is also a vital tool for cybersecurity professionals. Here's why:

Vulnerability Scanning: Before launching a penetration test, security experts often enumerate subdomains to identify potential weak points. The more subdomains they're aware of, the more comprehensive their tests can be.

Phishing Detection: Malicious actors often create subdomains under legitimate-looking domains to deceive users. By regularly monitoring and understanding the subdomains associated with a primary domain, businesses can detect suspicious activity early.

Asset Management: Large organizations with multiple online services can use this tool to maintain an inventory of their web assets, ensuring no subdomain goes unnoticed or unchecked.

SEO and Brand Monitoring: Brands can monitor subdomains to detect potential infringements or misuse of their brand name in URLs.

This CLI tool provides a fast and reliable way to fetch subdomains, aiding both in developmental operations and security assessments. Whether you're a website administrator, a developer, or a security expert, this tool is designed to make your life easier and your operations more secure.

At the core of the Subdomains CLI Tool's performance and efficiency is the Go programming language (often referred to as Golang). Here's a brief overview of how Go contributes to the tool's prowess:

Concurrency with Goroutines: Go is inherently designed for concurrency. It uses 'goroutines', which are lightweight threads managed by the Go runtime. This means our tool can execute multiple tasks concurrently, such as making multiple API requests or processing multiple subdomains simultaneously, without the overhead of traditional heavyweight threads.

Channels for Communication: Channels in Go provide a way for goroutines to communicate with each other and synchronize their execution. In the context of our tool, channels ensure that data (like subdomains) is seamlessly passed between different parts of the program and that all tasks complete as intended.

Efficient Compilation: Go compiles to machine code. This means that the tool doesn't rely on an interpreter or a virtual machine, leading to faster execution times.

Optimized for Networking: Go has a powerful standard library, especially for networking tasks. This ensures efficient and robust network calls when our tool queries the subdomain.center API.

Memory Management: Go uses a garbage collector optimized for low-latency scenarios. This means our tool manages memory efficiently without manual intervention, ensuring that it remains performant even with large datasets.

In essence, the combination of Go's design principles, its focus on concurrency, and its robust standard library means that the Subdomains CLI Tool can deliver results quickly and effectively, making it a preferred choice for those who need to fetch subdomains in real-time or at scale.

• Go: Ensure you have Go installed. If not, you can download and install it from Go's official website.

1. Clone the Repository:

   git clone https://github.com/rajibmitra/subDomain.git
   cd subDomain
   

2. Build the Tool:

   go build -o subdomains .
   
   This command compiles the code and produces a binary named subdomains.
      
   (Optional) Add to PATH:
   If you want to use the tool from any directory, move the subdomains binary to a directory in your PATH or add the current directory to your PATH.
   

3. Download from release If you are unable to build the tool - goto https://github.com/rajibmitra/subDomain/releases/tag/1.0.0 Download the binary as per your need, and use it.

   subdomains [flags] [domain] Flags: -u, --url: Domain to fetch subdomains for. -o, --output: Output format. Currently, only "txt" is supported, which writes the subdomains to a file named subdomains.txt.

   Examples:

   Fetch subdomains for xyz.com and print them in the console: ./subdomains -u xyz.com

   Fetch subdomains for xyz.com and write them to subdomains.txt: ./subdomains -u xyz.com -o txt

   

   Contributing

   Pull requests are welcome. For major changes, please open an issue first to discuss what you would like to change.

   License

   Licensed under the Apache 2 License.