Pass exit code properly

[hyperupcall]

This entails creating a first function for codes that require it (or all of them for consistency) and adding a global variable with $?, since $? will get clobbered

[hyperupcall]

I don't know what this means

[hyperupcall]

This means that on trapping ERR, if we do exit 1, the rest of the functions are not called. And if they are, then $? will be clobbered and not be the true exit code (that for example may be shown in the stack trace)