Improve error when executing `run.sh` from wrong directory

[BenjaminRodenberg]

I think for every (?) run.sh file it is necessary to run it from the folder of the participant (e.g. partitioned-heat-conduction/dirichlet-fenics). Running ./dirichlet-fenics/run.sh from partitioned-heat-conduction is incorrect and results in the error:

ERROR: Could not open requirements file: [Errno 2] No such file or directory: '../solver-fenics/requirements.txt'

Is it possible to improve this error? Basically we have to make sure that we always execute run.sh from its parent directory.

[MakisH]

First of all: yes, it would be nice to catch the user mistake earlier.

From some (very short) previous research around the topic, I understood that the ways to do this in the run scripts are mostly shell-specific and not very standard. But I would be happy with any solution that passes shellcheck.

In the meantime, we have switched our scripts from sh to bash, so we have more options.

[uekerman]

Side note: In the application guidelines, we (will) specify that these script are supposed to be called from the subfolders.

And we also have this in the tutorial docs already.