Overview of Unix System Calls

Unix system calls are functions provided by the Unix operating system kernel, which allow user-level applications to interact with the operating system. These system calls provide a way for applications to request various services from the operating system, such as file I/O, process management, networking, and memory management.

Some commonly used Unix system calls include:

• open() and close() for opening and closing files
• read() and write() for reading from and writing to files
• fork() and exec() for creating new processes and executing new programs
• exit() for terminating a process
• socket() and bind() for creating and binding network sockets
• accept() and connect() for establishing network connections
• malloc() and free() for memory allocation and deallocation

Unix system calls are typically accessed through a set of library functions known as the "C library", which provides a higher-level interface to the system calls. Many programming languages, including C, C++, and Python, provide wrappers for Unix system calls, allowing applications to access these low-level operating system services. Understanding Unix system calls and how to use them can be important for developing efficient, low-level applications on Unix-based systems.