Fix shellcheck errors and warnings

**Description**

The scripts at `/library-scripts` are functional but do throw shellcheck warnings and errors.

We should fix these as best as within reason.

**Steps to Reproduce**
Steps to reproduce the behavior:
1. Open the repository with the devcontainer
2. The .sh files should light up yellow with warnings

**Expected behavior**

A clean repository that follows best practices as much as possible.

**Actual behavior**

The scripts at `/library-scripts` are functional but do throw shellcheck warnings and errors.