Bash error: "cannot execute binary file: Exec format error"

Error String

bash: ./program: cannot execute binary file: Exec format error

Tldr

This means the kernel could not load the file as an executable — either it is a compiled binary built for a different CPU architecture (e.g. an ARM binary on x86_64), or a script with no valid shebang line, or a shell script mistakenly marked and executed as a binary. Check the file type with `file` and re-run through the correct interpreter or architecture.

Cause

Every executable file starts with a format the kernel recognizes: ELF headers for native binaries, or "#!" for interpreted scripts. Exec format error happens when neither matches — you copied an ARM/aarch64 binary onto an x86_64 machine (common with Docker images built on Apple Silicon), you tried to execute a script that lost its shebang line, or the shebang points somewhere invalid so the kernel falls back to interpreting garbage as a binary.

Repro

$ file ./app
app: ELF 64-bit LSB executable, ARM aarch64, ...

$ ./app
bash: ./app: cannot execute binary file: Exec format error

Fix

#!/usr/bin/env bash
set -euo pipefail

# Confirm the mismatch
file ./app
uname -m

# Option 1: run under emulation (Docker buildx / qemu)
docker run --platform linux/amd64 myimage ./app

# Option 2: rebuild for the target architecture
GOARCH=amd64 GOOS=linux go build -o app

# Option 3: for scripts, ensure a valid shebang exists
head -c2 script.sh   # should print "#!"
sed -i '1i #!/usr/bin/env bash' script.sh   # if missing

Explanation

Use `file <path>` first — it tells you immediately whether you have a script, an ELF binary, and for which architecture. On Apple Silicon Macs, cross-building Docker images without --platform is the most common cause; use `docker buildx build --platform linux/amd64,linux/arm64`.

Faq