Liangxu Linux

May 18, 2021 · Fundamentals

What Exactly Is a File Descriptor (fd) in Linux? A Deep Dive into Kernel Structures

This article explains the true nature of a file descriptor (fd) in Linux, tracing how the kernel represents open files through task_struct, files_struct, fdtable, and inode structures, and shows how these layers interact with system calls like open, read, write, dup, and fork.