An "exec format error" occurs when the operating system cannot execute a file because its format is not compatible with the system’s architecture or environment. This typically happens when a binary compiled for one architecture (e.g., x86_64) is run on a different one (e.g., ARM), or when a script lacks proper execution instructions.

A common scenario is running a binary built for a different platform, such as executing an AMD64 program on a Raspberry Pi, which uses ARM. Another trigger is attempting to run a script (like a Bash or Python script) without a proper shebang line (#!/bin/bash or #!/usr/bin/python3). Without this, the OS doesn’t know how to interpret the script content.

To fix this, ensure the binary matches your system’s architecture using file your_binary or uname -m. If it's a script, verify it starts with a valid shebang and has executable permissions (chmod +x script.sh). For containers or cross-platform deployments, always build your executables for the correct target architecture. Read more at https://perimattic.com/fix-exec-format-error/