A Deep Dive into the ELF File Format
Elf Quest

© Photo by erin mckenna on Unsplash
Linux and other Unix-based systems use the ELF file format for executables, object code, and shared libraries. Take a peek inside to learn how an ELF file is organized.
An object file is a black box that you can never really see inside. You can't just open it and read it. We all have some understanding that it contains instructions for the computer, coded in a format that only a computer can understand, but we're used to thinking of compiled program code as something of a mystery. If you take a closer look, however, the structure is not as opaque as you might imagine.
Linux, like most other Unix-like operating systems, stores program code in the Executable and Linkable Format (ELF). ELF superseded the less-flexible a.out
format and has been the standard in Linux since 1995 and in FreeBSD [1] since 1998. An ELF object file contains the processor-specific instructions that the CPU actually executes. It also contains other information relating to
- how and where to load the object into memory
- dynamic linking
- any public functions exported (or imported) by the object
- debugging
[...]
Buy this article as PDF
(incl. VAT)
Buy Linux Magazine
Subscribe to our Linux Newsletters
Find Linux and Open Source Jobs
Subscribe to our ADMIN Newsletters
Support Our Work
Linux Magazine content is made possible with support from readers like you. Please consider contributing when you’ve found an article to be beneficial.

News
-
Kali Linux 2025.3 Released with New Hacking Tools
If you're a Kali Linux fan, you'll be glad to know that the third release of this famous pen-testing distribution is now available with updates for key components.
-
Zorin OS 18 Beta Available for Testing
The latest release from the team behind Zorin OS is ready for public testing, and it includes plenty of improvements to make it more powerful, user-friendly, and productive.
-
Fedora Linux 43 Beta Now Available for Testing
Fedora Linux 43 Beta ships with Gnome 49 and KDE Plasma 6.4 (and other goodies).
-
USB4 Maintainer Leaves Intel
Michael Jamet, one of the primary maintainers of USB4 and Thunderbolt drivers, has left Intel, leaving a gaping hole for the Linux community to deal with.
-
Budgie 10.9.3 Now Available
The latest version of this elegant and configurable Linux desktop aligns with changes in Gnome 49.
-
KDE Linux Alpha Available for Daring Users
It's official, KDE Linux has arrived, but it's not quite ready for prime time.
-
AMD Initiates Graphics Driver Updates for Linux Kernel 6.18
This new AMD update focuses on power management, display handling, and hardware support for Radeon GPUs.
-
AerynOS Alpha Release Available
With a choice of several desktop environments, AerynOS 2025.08 is almost ready to be your next operating system.
-
AUR Repository Still Under DDoS Attack
Arch User Repository continues to be under a DDoS attack that has been going on for more than two weeks.
-
RingReaper Malware Poses Danger to Linux Systems
A new kind of malware exploits modern Linux kernels for I/O operations.