Exiting after failing commands is pretty unacceptable

[gregmcinnes]

I was excited to find this library but I don't think I can use it and feel confident running it at any sort of scale. It really needs to throw an error and report the error message if the underlying command fails. Otherwise it's difficult to trust anything that's run with this library.

I was contemplating creating a "success" file after the bcftools and running a separate script that checks for the success file, but that should not be necessary.

[leeleavitt]

It can be painful to debug, but please be more empathetic when you write these issues down.

[jmarshall]

Duplicate of #506