Wrap lines at 80 columns where appropriate and I had the energy to think
about how/where to wrap.
There are still lines longer than that, which I plan to wrap in the
future. But that is enough for now.
Replace all occurrences of [ with [[ in bash and zsh scripts and
configs.
Performance wise it makes sense to use the builtin instead of calling an
external command also when from a functionality stand point `test` would
suffice.
