About

readelf.com is an independent reference for people who have to make a binary run on a machine that is not the one it was built on.

Who writes this

My name is luckyray. I am a Linux and infrastructure engineer — the person who gets called when a service will not start and the error message is three words long. Most of my working life has been spent on Debian and RHEL fleets, container platforms, and the unglamorous middle layer where packaging, the dynamic loader and the kernel meet.

Everything on this site comes from that work. The guides are written from incidents I have actually debugged, and the tools were built because I kept needing them on hosts where I could not install anything.

You can find me on GitHub. This site is a personal project: it is not affiliated with, sponsored by, or operated on behalf of any employer or client, and nothing here should be read as their opinion.

Why the site exists

Two things make this material hard to find done well. The first is that the authoritative sources are excellent but scattered: the ELF specification, the glibc manual, and the ld.so man page each describe part of the picture, and none of them describes what happens when the parts interact badly. The second is that the error messages are terse to the point of being misleading — No such file or directory when the file is right there is the classic example.

So the aim is narrow and specific: take one error message, explain the mechanism that produces it, show the commands that confirm the diagnosis, and be explicit about when the suggested fix is a workaround rather than a fix. If a technique is dangerous, the guide says so — copying libc.so.6 between machines is covered because people do it, not because it is recommended.

How the tools are built

All four tools run entirely in your browser. Files are read with the File API, parsed in JavaScript, and never transmitted. There is no upload endpoint on this site, which means there is nothing to breach and nothing to retain. The methodology page documents exactly which fields are read and which rules are used to derive the summary verdicts, so you can verify any result with readelf yourself.

How the site is funded

Hosting costs are near zero by design — this is a static site served from a small single-board computer behind a Cloudflare tunnel. Advertising covers the rest. Ads are the only commercial element: no affiliate links, no sponsored posts, no tracking pixels, and no analytics that follow you between sites.

Corrections

If something here is wrong, I want to know. Technical corrections are the most useful mail this site receives, and they get fixed with the reasoning attached rather than silently edited. Use the contact page.