Permission denied on Chromebook even with sudo

Question

When I compile my C++ code on my Chromebook's shell, I get the error bash: ./a.out: Permission denied. This happens even when I run with sudo: sudo: unable to execute ./a.out: Permission denied. Why does this happen?

Answer 1

The problem ended up being that the filesystem was mounted with the noexec flag, probably for security reasons. To get around this,

1. Run sudo mount -o remount,rw -o exec PATH/TO/YOUR/FILE, where PATH/TO/YOUR/FILE is the directory where you're trying to execute the file.
2. If you get an error like mount: /home/chronos/user/Downloads not mounted or bad option, remove the last directory from the command (in this case /Downloads) and try again. Keep removing until it works.
3. If you get an error like When remounting eCryptfs, you need to pass the mount utility the -i parameter to avoid calling the mount helper, run sudo mount -o remount,rw -io exec PATH/TO/YOUR/.

You should now be able to run the file.