"sh: ./<file> not found" error when trying to execute a file
arm, buildroot, c++, linux, sh
Solution
`sh` prints this weird error because it is trying to run your program as a shell script!
Your error `./hw: not found` is probably caused by the dynamic linker (AKA ELF interpreter) not being found. Try compiling it as a static program with `-static` or running it with your dynamic loader: `# /lib/ld-linux.so.2 ./hw` or something like that.
If the problem is that the dynamic loader is named differently in your tool-chain and in your runtime environment you can fix it:
- In the runtime environment: with a symbolic link.
- In the tool-chain: use `-Wl,--dynamic-linker=/lib/ld-linux.so.2`
Problem
I've come across a weirdest problem I ever met. I'm cross-compiling an app for ARM CPU with Linux on-board. I'm using buildroot, and all goes well until I'm trying to run the application on the target: I'm getting `-sh: ./hw: not found`. E.g.: ``` $ cat /tmp/test.cpp #include <cstdio> #include <vector> int main(int argc, char** argv){ printf("Hello Kitty!\n"); return 0; } $ ./arm-linux-g++ -march=armv7-a /tmp/test.cpp -o /tftpboot/hw ``` load the executable to the target; then issuing on the target: ``` # ./hw -sh: ./hw: Permission denied # chmod +x ./hw # ./hw -sh: ./hw: not found # ls -l ./hw -rwxr-xr-x 1 root root 6103 Jan 1 03:40 ./hw ``` There's more to it: upon building with distro compiler, like `arm-linux-gnueabi-g++ -march=armv7-a /tmp/test.cpp -o /tftpboot/hw`, the app runs fine! I compared executables through `readelf -a -W /tftpboot/hw`, but didn't notice much defference. I pasted both outputs here. The only thing I noticed, are lines `Version5 EABI, soft-float ABI` vs `Version5 EABI`. I tried removing the difference by passing either of `-mfloat-abi=softfp` and `-mfloat-abi=soft`, but compiler seems to ignore it. I suppose though, this doesn't really matter, as compiler doesn't even warn. I also thought, perhaps sh outputs this error if an executable is incompatible in some way. But on my host PC I see another error in this case, e.g.: ``` $ sh /tftpboot/hw /tftpboot/hw: 1: /tftpboot/hw: Syntax error: word unexpected (expecting ")") ```