I am doing time lapse with gphoto2 and EOS 550D and mirror lockup. Due to MLU, I have to trigger the shutter twice (through an serial port controlled shutter release) for each frame, once to raise the mirror, and a second time to expose. As a result, some communication between my time lapse script and gphoto2 is required. I use a hook-script which creates or deletes files _gphoto.init and/or _gphoto.start so that the main script knows the status of gphoto2. This allows the time lapse script to know when it is safe to trigger the shutter.
In one run, I received the error:
execve("hook-script.sh") failed: Input/output error Hook script returned error code 1 (0x1) Hook script "hook-script.sh" init failed. Aborting.
and in another run: /bin/sh: Can't open hook-script.sh Hook script returned error code 1 (0x1) Hook script "hook-script.sh" init failed. Aborting.
I doubt it is a coding error in hook-script.sh, as I've used this hook-script many times. So I think a rare condition (filesystem problem?) that causes the hook-script execution to fail once in a while. How can I recover from this failure? Once the error occurs, the time lapse hangs.