Writing a Linux x86 Program Without an Interpreter, Compiler, or Assembler

📝By manually writing machine code, you can create a Linux x86 program without the need for an interpreter, compiler, or assembler.

💻Executable files are binary files that contain machine code instructions in hexadecimal form.

🔁You can use tools like xxd to create a hex dump of an executable file, which allows you to inspect or edit it.

✏️Editing executable files requires modifying the machine code instructions directly, taking care not to break the program's functionality.

🔀After modifying the hex dump, you can reverse the process using xxd's reverse mode to convert it back to a binary file.

Can I edit executable files using an ordinary text editor?

—No, executable files are binary files and cannot be edited using a regular text editor. You need to use tools like xxd to convert them to a readable format.

Is it safe to edit executable files directly?

—Editing executable files can be risky, as any mistakes in modifying the machine code can cause the program to stop functioning properly. It requires a deep understanding of the program's structure and functionality.

How do I convert a modified hex dump back to a binary file?

—You can use the reverse mode of the xxd tool to convert a modified hex dump back to a binary file. This allows you to apply your changes to the executable program.

What precautions should I take when editing executable files?

—When editing executable files, it's crucial to have a backup of the original file in case something goes wrong. Additionally, make sure to only modify the necessary parts and double-check your changes to avoid introducing errors.

Can I use this method to modify any executable file?

—Yes, this method can be used to modify any executable file. However, it's important to note that changing the machine code of a program can have unintended consequences, so it should be done with caution.

00:00In this video, we learn how to write a Linux x86 program without using an interpreter, compiler, or assembler by crafting machine code manually.

03:36Executable files are binary files containing machine code instructions in hexadecimal form. Ordinary text editors cannot be used to edit them.

05:56Tools like xxd can be used to create a hex dump of an executable file, allowing for inspection and editing.

09:20Editing executable files requires modifying the machine code instructions directly, ensuring that the program's functionality is not compromised.

10:46After modifying the hex dump, the reverse mode of xxd can be used to convert it back to a binary file.